diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2591549ef..d9e4be0fe 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -62,7 +62,7 @@ accept your pull requests.
    The below command should be run from the root of the source code:
 
    ```
-   node build/src/bin/release-please.js release-pr \
+   npm run compile && node build/src/bin/release-please.js release-pr \
    --token=$GITHUB_TOKEN \
    --repo-url=<owner>/<repo> [extra options]
    ```
diff --git a/__snapshots__/github.js b/__snapshots__/github.js
index af1c14c8b..a7900800b 100644
--- a/__snapshots__/github.js
+++ b/__snapshots__/github.js
@@ -11,6 +11,7 @@ exports['GitHub commitsSince backfills commit files for pull requests rebased an
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-rebase-merge",
+      "mergeCommitOid": "b29149f890e6f76ee31ed128585744d4c598924c",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -28,6 +29,7 @@ exports['GitHub commitsSince backfills commit files for pull requests rebased an
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-rebase-merge",
+      "mergeCommitOid": "b29149f890e6f76ee31ed128585744d4c598924c",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -48,6 +50,7 @@ exports['GitHub commitsSince backfills commit files for pull requests with lots
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -68,6 +71,7 @@ exports['GitHub commitsSince backfills commit files without pull requests 1'] =
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -86,6 +90,7 @@ exports['GitHub commitsSince finds commits up until a condition 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -104,6 +109,7 @@ exports['GitHub commitsSince finds first commit of a multi-commit merge pull req
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -119,6 +125,7 @@ exports['GitHub commitsSince finds first commit of a multi-commit merge pull req
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "b29149f890e6f76ee31ed128585744d4c598924c",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -134,6 +141,7 @@ exports['GitHub commitsSince finds first commit of a multi-commit merge pull req
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "27d7d7232e2e312d1380e906984f0823f5decf61",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -152,6 +160,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -167,6 +176,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "b29149f890e6f76ee31ed128585744d4c598924c",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -182,6 +192,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "27d7d7232e2e312d1380e906984f0823f5decf61",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -197,6 +208,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "2b4e0b3be2e231cd87cc44c411bd8f84b4587ab5",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -212,6 +224,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "a257514a541d483425118d973674b1ce006a5489",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -227,6 +240,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "b6a8ab1a50106cfb03f22c2cdaf7abfdcccce088",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -242,6 +256,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "520b6f42551c86002197d033564a76a3f99b0019",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -257,6 +272,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 3,
       "baseBranchName": "main",
       "headBranchName": "release-please/branches/main",
+      "mergeCommitOid": "9dda1a331d311d0a7643015cc9e6802548c8d943",
       "title": "chore(main): release 0.1.1-SNAPSHOT",
       "body": ":robot: I have created a release \\*beep\\* \\*boop\\* \n---\n### Updating meta-information for bleeding-edge SNAPSHOT release.\n---\n\n\nThis PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).",
       "labels": [
@@ -274,6 +290,7 @@ exports['GitHub commitsSince limits pagination 1'] = [
       "number": 2,
       "baseBranchName": "main",
       "headBranchName": "feature-branch",
+      "mergeCommitOid": "e86984fb22ccc5eafb6c3d815851ade3463193da",
       "title": "feat: feature-branch that will be squash merged",
       "body": "",
       "labels": [],
@@ -296,6 +313,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -311,6 +329,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "b29149f890e6f76ee31ed128585744d4c598924c",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -326,6 +345,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "27d7d7232e2e312d1380e906984f0823f5decf61",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -341,6 +361,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "2b4e0b3be2e231cd87cc44c411bd8f84b4587ab5",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -356,6 +377,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "a257514a541d483425118d973674b1ce006a5489",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -371,6 +393,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "b6a8ab1a50106cfb03f22c2cdaf7abfdcccce088",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -386,6 +409,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 6,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-merge",
+      "mergeCommitOid": "520b6f42551c86002197d033564a76a3f99b0019",
       "title": "feat: feature that will be rebase merged",
       "body": "",
       "labels": [],
@@ -401,6 +425,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 3,
       "baseBranchName": "main",
       "headBranchName": "release-please/branches/main",
+      "mergeCommitOid": "9dda1a331d311d0a7643015cc9e6802548c8d943",
       "title": "chore(main): release 0.1.1-SNAPSHOT",
       "body": ":robot: I have created a release \\*beep\\* \\*boop\\* \n---\n### Updating meta-information for bleeding-edge SNAPSHOT release.\n---\n\n\nThis PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please).",
       "labels": [
@@ -418,6 +443,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 2,
       "baseBranchName": "main",
       "headBranchName": "feature-branch",
+      "mergeCommitOid": "e86984fb22ccc5eafb6c3d815851ade3463193da",
       "title": "feat: feature-branch that will be squash merged",
       "body": "",
       "labels": [],
@@ -437,6 +463,7 @@ exports['GitHub commitsSince paginates through commits 1'] = [
       "number": 1,
       "baseBranchName": "main",
       "headBranchName": "release-release-please-test-v0.1.0",
+      "mergeCommitOid": "959ee48c95f254300eb040c46ebdc8248317efe4",
       "title": "Release release-please-test v0.1.0",
       "body": "This pull request was generated using releasetool.\n\n02-03-2021 11:56 PST\n\n### New Features\n- feat: initial commit\n\n### Internal / Testing Changes\n- build: add java structure",
       "labels": [
@@ -531,6 +558,7 @@ exports['GitHub mergeCommitIterator handles merged pull requests without files 1
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "e6daec403626c9987c7af0d97b34f324cd84320a",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
@@ -546,6 +574,7 @@ exports['GitHub mergeCommitIterator handles merged pull requests without files 1
       "number": 7,
       "baseBranchName": "main",
       "headBranchName": "feature-branch-plain-merge",
+      "mergeCommitOid": "b29149f890e6f76ee31ed128585744d4c598924c",
       "title": "feat: feature that will be plain merged",
       "body": "",
       "labels": [],
diff --git a/src/github.ts b/src/github.ts
index 0b581b646..f36a98f15 100644
--- a/src/github.ts
+++ b/src/github.ts
@@ -510,6 +510,7 @@ export class GitHub {
           number: pullRequest.number,
           baseBranchName: pullRequest.baseRefName,
           headBranchName: pullRequest.headRefName,
+          mergeCommitOid: pullRequest.mergeCommit?.oid,
           title: pullRequest.title,
           body: pullRequest.body,
           labels: pullRequest.labels.nodes.map(node => node.name),
diff --git a/src/manifest.ts b/src/manifest.ts
index 5226ac21f..281e20ee7 100644
--- a/src/manifest.ts
+++ b/src/manifest.ts
@@ -1575,7 +1575,7 @@ async function latestReleaseVersion(
   for await (const commitWithPullRequest of generator) {
     commitShas.add(commitWithPullRequest.sha);
     const mergedPullRequest = commitWithPullRequest.pullRequest;
-    if (!mergedPullRequest) {
+    if (!mergedPullRequest?.mergeCommitOid) {
       logger.trace(
         `skipping commit: ${commitWithPullRequest.sha} missing merged pull request`
       );
diff --git a/src/pull-request.ts b/src/pull-request.ts
index a44feaee1..9176207d4 100644
--- a/src/pull-request.ts
+++ b/src/pull-request.ts
@@ -16,6 +16,7 @@ export interface PullRequest {
   readonly headBranchName: string;
   readonly baseBranchName: string;
   readonly number: number;
+  readonly mergeCommitOid?: string;
   readonly title: string;
   readonly body: string;
   readonly labels: string[];
diff --git a/test/manifest.ts b/test/manifest.ts
index 7315dee0c..cbf259f02 100644
--- a/test/manifest.ts
+++ b/test/manifest.ts
@@ -1423,6 +1423,7 @@ describe('Manifest', () => {
             title: 'chore: release 1.2.3',
             headBranchName: 'release-please/branches/main',
             baseBranchName: 'main',
+            mergeCommitOid: 'abc123',
             number: 123,
             body: '',
             labels: [],