How do I use GitLineHandler to retrieve the logs of a user?

I can successfully obtain logs in the following ways.
 

val handler = GitLineHandler(project, repo.root, GitCommand.LOG)
val result = Git.getInstance().runCommand(handler)
if (result.success()) {
    result.output.forEach { line
        println(line)
    }
}

When I try to retrieve the logs of a specific user, it returns empty.

val handler = GitLineHandler(project, repo.root, GitCommand.LOG)
handler.addParameters("--committer=\"coolbee\"")
val result = Git.getInstance().runCommand(handler)
if (result.success()) {
    result.output.forEach { line
        println(line)
    }
}

I also tried to change --committer to --author, but it didn't help. Did I miss something?