They claim evidence shows he "had a history of obsession with violent ideations."

Officials in Dayton held a press conference Tuesday afternoon to give the latest on Sunday's mass shooting that left nine people dead and more than 20 injured.

Authorities gave a little more information on the suspected shooter, Connor Betts of Bellbrook, Ohio. They claim evidence shows he "had a history of obsession with violent ideations" and "had expressed a desire to commit a mass shooting."

The FBI has joined the investigation into the mass murder, handling aspects of the killer's background while the Dayton Police Department will handle the homicide aspects. Despite the somewhat clearer picture of the suspect, police say an exact motive is still not known.

Dayton Mayor Nan Whaley was also there, and held a news conference of her own this morning outside Ned Peppers, a bar on 5th Street in the city's Oregon District where the shooting took place. In her remarks, she confirmed President Donald Trump would be coming to the city on Wednesday and that she will meet with him personally during his visit.

However, Whaley also criticized the president for being "unhelpful" in combating gun violence, and also encouraged those in Dayton unhappy with him to exercise their first amendment rights tomorrow.

"I know that he's made this bed, he's got to lie in it," Whaley said, adding she will bring her criticisms directly to Trump when she sees him. "His rhetoric has been painful for many in our community and I think that people should stand up and say they're not happy if they're not happy he's coming."

Whaley also gave her thoughts on the latest gun safety proposals offered by Ohio Gov. Mike DeWine. While she admitted she would like the governor to go further with gun control, she did praise him for for taking steps and "[listening] to the people of Dayton."

"I'm not pollyannish to think that we're going to find the perfect answer of legislation that's going to solve every single gun problem down the road," she told reporters. "But we need to start working and moving towards that direction."

Police say Connor Betts drove to the Oregon District with his sister, Megan Betts, and another man early Sunday. Sometime after his arrival, the shooter separated from his sister Megan and their third companion. Police believe it was during this time that he retrieved his weapon, an "AR-15 like" rifle.

The shooter is said to have committed all of the killings in a span of 30 seconds before he himself was shot dead by officers.