diff --git a/docs/admin_api/user_admin_api.md b/docs/admin_api/user_admin_api.md
index 3625c7b6c5..880bef4194 100644
--- a/docs/admin_api/user_admin_api.md
+++ b/docs/admin_api/user_admin_api.md
@@ -37,6 +37,7 @@ It returns a JSON body like the following:
"is_guest": 0,
"admin": 0,
"deactivated": 0,
+ "erased": false,
"shadow_banned": 0,
"creation_ts": 1560432506,
"appservice_id": null,
@@ -167,6 +168,7 @@ A response body like the following is returned:
"admin": 0,
"user_type": null,
"deactivated": 0,
+ "erased": false,
"shadow_banned": 0,
"displayname": "<User One>",
"avatar_url": null,
@@ -177,6 +179,7 @@ A response body like the following is returned:
"admin": 1,
"user_type": null,
"deactivated": 0,
+ "erased": false,
"shadow_banned": 0,
"displayname": "<User Two>",
"avatar_url": "<avatar_url>",
@@ -247,6 +250,7 @@ The following fields are returned in the JSON response body:
- `user_type` - string - Type of the user. Normal users are type `None`.
This allows user type specific behaviour. There are also types `support` and `bot`.
- `deactivated` - bool - Status if that user has been marked as deactivated.
+ - `erased` - bool - Status if that user has been marked as erased.
- `shadow_banned` - bool - Status if that user has been marked as shadow banned.
- `displayname` - string - The user's display name if they have set one.
- `avatar_url` - string - The user's avatar URL if they have set one.
@@ -1193,3 +1197,42 @@ Returns a `404` HTTP status code if no user was found, with a response body like
```
_Added in Synapse 1.68.0._
+
+
+### Find a user based on their Third Party ID (ThreePID or 3PID)
+
+The API is:
+
+```
+GET /_synapse/admin/v1/threepid/$medium/users/$address
+```
+
+When a user matched the given address for the given medium, an HTTP code `200` with a response body like the following is returned:
+
+```json
+{
+ "user_id": "@hello:example.org"
+}
+```
+
+**Parameters**
+
+The following parameters should be set in the URL:
+
+- `medium` - Kind of third-party ID, either `email` or `msisdn`.
+- `address` - Value of the third-party ID.
+
+The `address` may have characters that are not URL-safe, so it is advised to URL-encode those parameters.
+
+**Errors**
+
+Returns a `404` HTTP status code if no user was found, with a response body like this:
+
+```json
+{
+ "errcode":"M_NOT_FOUND",
+ "error":"User not found"
+}
+```
+
+_Added in Synapse 1.72.0._
|