Harley was arrested for domestic battery on Sunday night

Ronnie Ortiz-Magro and Jen Harley got into a heated argument before she was arrested for domestic battery on Sunday night.

A source tells PEOPLE the Jersey Shore star and his ex initially got into a “verbal fight” at a barbecue with friends that day. According to the source, they left with their 12-week-old daughter in the backseat of the car. On the drive home, “the fight escalated” and Harley “was pummeling his face,” says the source.

“He was screaming for her to stop the car as she was driving,” says the source. “She hit the median and got a flat tire which caused her to slow down. He begged to get out and opened the door but she continued to pull away while he was getting out and it tore up his entire arm. It’s a mess from road rash and from being dragged along the street as he was caught in the belt.”

According to the source, “someone on the road saw this happening and called the police.”

“By the time it was said and done there were four flat tires,” says the source. “Police arrived and spoke to the many witnesses. They saw Ron’s arm and spoke to him and then arrested Jen. His face is all busted up from her pummeling him.” (The Las Vegas Metropolitan Police Department did not immediately respond to PEOPLE’s request for comment; PEOPLE confirmed via online records for the Clark County Detention Center that Harley, 31, was arrested for domestic battery on Sunday night.)

The source said it was “100 percent intentional” and Harley was “beating [Ortiz-Magro] up.”

“She wasn’t drinking at the party as she was driving, so she was sober,” adds the source.

Ronnie Ortiz-Magro's ex-girlfriend arrested for alleged domestic violence.
Jen Harley
| Credit: LVMPD/Splash News

MTV had no comment when reached by PEOPLE. A rep for Ortiz-Magro had no comment when reached by PEOPLE; Harley was unable to be reached.

The source says a mutual friend took care of the exes’ infant daughter while Harley was being arrested, noting that “everybody is so fearful for this baby.”

According to the source, Ortiz-Magro, 32, had been “trying his best” to make things work with Harley for the sake of their daughter.

“If the kid wasn’t involved, it would be over,” says the source. “He’s constantly trying to make it work for the sake of his daughter. But we’re hopeful this is the final straw and he doesn’t put himself and his daughter back in danger.”

“He’s not perfect, but she’s the aggressor in this relationship,” adds the source. “It’s obvious with her pattern of behavior.”

Jen Harley and Ronnie Ortiz-Magro
| Credit: Jen Harley/Instagram

The Clark County Detention Center confirmed to PEOPLE on Tuesday that Harley had posted bond and is no longer in their custody. It’s not immediately clear what time she was released.

The exes welcomed their first child together, daughter Ariana Sky, on April 3 and have been making headlines for their explosive altercations. Earlier this month, cops were called when they got into a heated argument at Planet Hollywood while Ortiz-Magro was shooting season 2 of Jersey Shore Family Vacation.