Marston Hefner, the oldest son of Hugh Hefner, was arrested after he allegedly attacked his Playmate of the Year girlfriend Claire Sinclair, according to reports.
Police were called to the residence Marston shares with Sinclair in Pasadena, Calif., after one of Sinclair's family members called 911, claiming Marston had attacked her.
Officers observed visible injuries on Sinclair's body, including bruises and red marks, and Marston admitted the two had gotten into an argument earlier.
He did not admit striking Sinclair, however.
Sinclair told cops Marston punched her, kicked her in the stomach and refused to let her leave the residence, however. The model called family members after the alleged attack. Family members then made the decision to contact the authorities.
After a brief investigation, Marston was arrested for misdemeanor domestic violence at around 11:15 p.m., and hauled off to a nearby police station.
Marston was released on $20,000 bail a few hours later.
Sinclar, 20, was Playboy's POTY 2011. Marson Hefner, 21, whose mom is Hugh's ex-wife Kimberley Conrad, has been dating her on-and-off since August 2010.