San Luis Obispo police arrested a 69-year-old man today after he allegedly punched two men in downtown San Luis Obispo.

The incident happened about 12:30 p.m. near the Downtown Centre, when police said a man believed to be a transient walked up to a 14-year-old girl, who was sitting on a city bench using her cell phone, and began to yell and scream at her for no apparent reason, according to a news release.

Avila Beach resident Joseph Shepard, 58, noticed the incident and thought the man was going to hit the girl, so he stepped between them. The man then punched Shepard in the face, police said.

Then 48-year-old Michael Flores of San Luis Obispo stepped in to assist Shepard, police said, and the man punched Flores in the chest.

A security guard was alerted and detained the suspect until police arrived. Shepard and Flores were not injured but chose to press charges.

Police arrested the transient on suspicion of misdemeanor battery; he remains in San Luis Obispo County Jail in lieu of $2,000 bail.