This KB discuss how to determine which user is responsible for certain events such as app deployment, app update, app restart, app restage, etc...
The complete list of events are listed here.
Use the cf events <app-name> command to list all events for a certain app. Here is a sample result, please note on the column actor (in red below) where it shows specific username made by a specific app event
time event actor description
2018-09-04T17:03:49.00-0700 audit.app.droplet.create admin
2018-09-04T17:03:28.00-0700 audit.app.update admin state: STARTED
2018-09-04T17:03:27.00-0700 audit.app.build.create admin
2018-09-04T17:03:24.00-0700 audit.app.upload-bits admin
2018-09-04T17:03:24.00-0700 audit.app.map-route admin
2018-09-04T17:03:24.00-0700 audit.app.create admin instances: 1, state: STOPPED, environment_json: [PRIVATE DATA HIDDEN]
Alternatively you can also use capi /v3/audit_events endpoint and look for actor section, sample below
"actor": {
"guid": "##########",
"type": "user",
"name": "admin"
}