Ohio’s governor, the Republican Mike DeWine, has urged the Republican-led state legislature to pass laws requiring background checks for nearly all gun sales and allowing courts to restrict firearms access for people perceived as threats following the mass shooting in Dayton that left nine people dead.

Persuading the state legislature to pass such proposals could be an uphill battle. It has given little consideration this session to those and other gun-safety measures already introduced by Democrats.

DeWine’s Republican predecessor, John Kasich, also unsuccessfully pushed for a so-called “red flag” law on restricting firearms for people considered threats.

DeWine on Tuesday said Ohio needs to do more while balancing people’s rights to own firearms and have due process. Police say there was nothing in the Dayton shooter’s background to prevent him from buying the firearm used.

The shooting outside a strip of nightclubs early on Sunday and another mass shooting in El Paso, Texas, during the past weekend left a combined total of 31 people dead and more than 50 injured in less than 24 hours.

The back-to-back shootings hours apart and 1,300 miles (2,092km) away from each other quickly turned political, with Washington lining up along typical party lines in response.

Donald Trump has been criticised for citing mental illness, the internet and video games as part of the problem, but steered away from talk of curbing sales of guns, including the military-style weapons believed to have been used in the attacks. Previous gun control measures have languished in the Republican-controlled Senate.

Police have said 24-year-old Connor Betts was wearing a mask and body armour when he opened fire. If all of the magazines he had with him were full, which has not been confirmed, he would have had a maximum of 250 rounds, said the police chief, Richard Biehl.

“To have that level of weaponry in a civilian environment is problematic,” Biehl added.

Betts had no apparent criminal record as an adult and police said there was nothing that would have prevented him from buying a gun. (Ohio law bars anyone convicted of a felony as an adult, or convicted of a juvenile charge that would have been a felony if they were 18 or older, from buying firearms.)

Two former classmates told the Associated Press that Betts was suspended during their junior year at Bellbrook high school after a hitlist was found scrawled in a school bathroom. That followed an earlier suspension after Betts came to school with a list of female students he wanted to sexually assault, according to the two classmates, a man and a woman who are both now 24 and spoke on condition of anonymity out of concern they might face harassment.

Others remembered how he tried to intimidate classmates.

“It’s baffling and horrible that somebody who’s been talking for 10 years about wanting to shoot people could easily, so easily, get access to a military-grade weapon and that much ammo,” said Hannah Shows, a former classmate who remembered seeing Betts look at people and imitate shooting at them.

“He was someone who enjoyed making people afraid,” she said.

Former Bellbrook high school classmate Addison Brickler rode the bus with Betts and said he taunted her regularly.

“He was the bully,” Brickler told the AP. “He used to make fun of me on the bus, talk about my weight, make me feel bad about myself. He would laugh and think it was funny, joke about it. We thought it was a normal thing.”

But the seemingly normal heckling turned scary one day when she said two police officers pulled Betts off their bus during her first few weeks of high school. When she arrived home that day, her mom sat her and her brother down to tell her the school principal had called – they had been named on Betts’s “hitlist”.

Betts disappeared from the halls of Bellbrook high school. Students were offered counseling, teachers checked on kids, and extra police officers were on hand. Brickler said Betts later returned to the school.

Others that had encounters with Betts, however, painted a different picture.

Brad Howard told reporters in Bellbrook on Sunday that he knew Betts from preschool through their high school graduation. “Connor Betts that I knew was a nice kid. The Connor Betts that I talked to, I always got along with well,” Howard said.

Bellbrook-Sugarcreek Schools would not comment and refused to release information about Betts, citing legal protections for student records.

Still unknown is whether Betts targeted any of the victims, including his 22-year-old sister, Megan, the youngest of the dead.

Authorities identified the other dead as Monica Brickhouse, 39; Nicholas Cumer, 25; Derrick Fudge, 57; Thomas McNichols, 25; Lois Oglesby, 27; Saeed Saleh, 38; Logan Turner, 30; and Beatrice N Warren-Curtis, 36.

A database by the Associated Press, USA Today and Northeastern University shows that there have been 23 mass killings so far this year, claiming the lives of 131 people. By comparison, 140 people died in mass killings in all of 2018. The database tracks every mass killing in the country dating back to 2006.