Mourners bring flowers to a makeshift memorial Aug. 6, 2019, for the slain and injured in the Oregon District after a mass shooting early Sunday in Dayton, Ohio.
Mourners bring flowers to a makeshift memorial, Aug. 6, 2019, for the slain and injured in the Oregon District after a mass shooting early Sunday in Dayton, Ohio.

Updated 8:25 pm EDT

While police in Dayton, Ohio search for a motive behind Sunday's mass shooting in the city's nightlife district, the FBI is looking into whether gunman Connor Betts was influenced by "violent ideologies."

This undated photo provided by the Dayton Police Department shows Connor Betts.

FBI agent Todd Wickerham told reporters Tuesday agents have evidence Betts was "exploring" such ideas, but gave no other details.

Wickerham said Betts had not been on the FBI's radar as someone to watch. He also said investigators are still looking to see if anyone helped Betts carry out his bloody rampage.

Betts was a 24-year-old community college student.  He killed nine people, including his own sister, and wounded 26. But accounts of people who knew him say he harbored violent thoughts for years.

While police look for a tangible explanation for mayhem Betts unleashed in Dayton's nightlife district, classmates who knew him at Bellbrook High School a decade ago say he was suspended from the school when they discovered he was keeping lists of boys he wanted to kill and girls he wanted to rape.

FILE - Bellbrook Police Chief Doug Doherty briefs the media near the family home of Dayton mass shooting suspect Connor Betts, in Bellbrook, Ohio, Aug. 5, 2019.

One classmate, Jessica Masseth, told The Daily Beast online news outlet that the list of girls included those who had turned him down for dates or thought they were better than him. The boys were those he viewed as competition or a threat in some way. The hit list was found written in a school bathroom, with police pulling Betts off a school bus so they could question him. After his suspension, he eventually was allowed to return to the school.

“In the texts, and on the lists, he talked about destruction and dismemberment," Masseth recalled. "I mean how did the police not know he was going to do something like what he did this weekend? Everyone knew he was not right.”

Police say he had no criminal record as an adult.

Adelia Johnson, who briefly dated Connor Betts, who fatally gunned down people on Sunday in Dayton, Ohio, speaks to members of the media in Belmont Park in Dayton, Aug. 6, 2019.

More recently, Caitlyn (Adelia) Johnson, 24, told the Toledo Blade newspaper that she met Betts in a psychology class they shared at Sinclair Community College and dated him briefly a few months ago. But she ended the relationship after several troubling incidents.

On their first date, she said Betts showed her video of a mass shooting and said he had knowledge of shooting tragedies in numerous cities. Johnson said Betts took her to a gun range and was along with him when he delivered a threatening letter to a former girlfriend.

When Johnson broke up with Betts, she asked a friend if she could stay overnight because she was "scared that he might try to hurt me or stalk me."

Betts was the lead singer in what acquaintances describe as a "pornogrind" band called "The Menstrual Munchies," which sang songs with extremely graphic and violent lyrics.

A Twitter account believed to belong to Betts showed extreme left-wing and anti-police retweets, along with tweets supporting Antifa, or anti-fascist, protesters.

The Twitter bio on the "iamthespookster" account said, "I'm going to hell and I'm not coming back."

But police in Dayton and Mayor Nan Whaley say they do not know what touched off Betts's barrage of gunfire. Police Chief Richard Biehl said he does not know whether Betts targeted his sister, 22 year-old Megan Betts.

Mayor Nan Whaley speaks to members of the media, Aug. 6, 2019, outside Ned Peppers bar in the Oregon District after a mass shooting early Sunday in Dayton.

President Donald Trump is visiting Dayton on Wednesday, to meet with survivors of the slaughter, along with local officials and police who spotted Betts and killed him within 30 seconds of him opening fire.

Trump is also headed to El Paso, Texas, where a gunman believed to be targeting Hispanics in the city along the U.S.-Mexican border, killed 22 people at a Walmart store on Saturday 13 hours before the attack in Dayton.

A suspect in the El Paso carnage, Patrick Crusius, 21, was arrested and jailed and is being questioned extensively by police. Prosecutors say Crusius will face murder charges that could lead to the death penalty if he is convicted.

Much more is known about Crusius's motive. He is suspected of posting a hate-filled, white supremacist manifesto on a website, with much of his bile directed at Hispanics. He is reported to have told police he went to the Walmart to kill as many Mexicans as possible.

His family issued a statement late Tuesday saying his actions were "apparently influenced by people we do not know and from ideas and beliefs that we do not accept or condone in any way."

The statement says Crusius was raised in a family that taught "love, kindness, respect, and tolerance" and rejected all forms of racism and violence.