Police were reportedly called to the former Prison Break star's Beverly Hills apartment on Saturday night (21Apr12) after a heated argument with ex-Playboy Playmate Ashley Mattingly got out of hand.
According to TMZ.com, Garrison had already left the scene by the time cops responded to the call, but an upset Mattingly was seen talking to officers about the bust-up outside his pad.
The incident is said to have occurred hours after Mattingly took to Twitter.com to announce the end of their relationship, writing, "sooo happy to be single again from @LaneGarrison9 bye bye :) hahahaha."
When one follower accused her of being mean, she hit back and suggested Garrison's bad behaviour was to blame for the split, posting: "no drunk a** is trying to brake (sic) into my apt (apartment)!"
Editors at TMZ claim Garrison is now under investigation for felony domestic violence. The actor has yet to speak to police or comment on the allegations.
The fall out comes two months after cops responded to another 911 call following reports of a domestic dispute between the couple.
An incident report for that altercation was filed but no arrests were made.