A young Arizona mother was caught on video lobbing punches at a school bus driver after accusing her of speaking badly about her daughter.

Hermenegilda Marquez, 27, was arrested April 17 and charged with one count of felony aggravated assault on a school employee.

Surveillance video released by the Mesa County Sheriff's Office shows the school bus stopping near an intersection to let several children off. 

The victim, as a 64-year-old substitute driver, told police that Marquez approached and began shouting at her.

As the students shuffled off the bus, Marquez demanded, 'Are you talking s*** about my daughter?'

Hermenegilda Marquez, 27, was arrested and charged with felony aggravated assault on a school employee after attacking a bus driver

Surveillance video shows the young mother boarding a school bus and shouting at the driver, accusing her of 'talking s***' about her daughter

The driver repeatedly tells her to get off the bus, but Marquez begins to lob punches and yank the driver's hair 

The driver didn't acknowledge her, so Marquez repeated herself and stormed on board, clad in a midriff-bearing top and denim shorts.

'No! Get off my bus,' the driver said. She later told police that she didn’t know Marquez or her daughter.

Two other parents began to lambast the driver. 'This is not the bus stop where you're supposed to be dropping off the kids,' one said, also boarding the bus. 'This is not the first time we have complained about you.'

'Okay. Get off my bus,' the driver repeated.

Marquez got off, but later climbed back on to confront the driver again. As the woman picked up a radio headset, Marquez swung at her.

The 27-year-old began to slap the victim in the head and face before 'closing her hands into fists and continuing to pummel the victim with both hands,' according to court documents.

She grabbed the radio cord while telling the bus driver to 'do something now' and get off the bus. 

A man, identified by police as Marquez's boyfriend, grabbed her and pulled her away.

Marquez climbed off the bus after the first confrontation, but later got back on to throw punches as the victim picked up a radio headset

Investigators wrote that Marquez showed no emotion when told that she was facing felony charges

The 27-year-old was already on unsupervised probation for assault when she was arrested on April 17

As she was being taken off the bus, Marquez gripped the driver’s hair with both hands and attempted to yank the woman from her seat. Luckily, the seatbelt stopped her. 

The driver radioed for help before she began screaming again. Police said her pacemaker began to shock her. She was later treated for minor injuries. 

There were 11 children on board when the attack occurred.

Marquez drove off but was swiftly identified and detained. At the time of her arrest, the 27-year-old was already on unsupervised probation for assault.

She said she understood her Miranda rights, then immediately invoked her right to counsel when asked if she knew why she had been arrested.

'The defendant was shown video of the attack on the bus and was told that because she was on video committing the assault, she would be charged with a felony,' investigators noted.

Marquez allegedly showed no emotion upon hearing the charges.