In the ongoing investigation into the attempted assassination of Donald Trump Saturday, FBI officials said "suspicious devices" were found in the suspected shooter, Thomas Matthew Crooks' car and home.

Pittsburgh Special Agent in Charge Kevin Rojek said there was a suspicious device found in the suspect's car and agents were trying to determine what it is.

Another was found in his home, Rojek said, and both were described as rudimentary.

Crooks had no known history of mental illness, per the FBI. His family is cooperating with investigators.

Milwaukee police said they don't have the authority to ban guns in the areas surrounding the Republican National Convention.

"Local ordinances in the state of Wisconsin do not supersede state law," Milwaukee Police Assistant Chief Steven Johnson said during a press briefing Sunday with the U.S. Secret Service, noting that because Wisconsin is an open carry state, no jurisdiction can supersede that state law.

"Folks should be aware of that," Johnson added.

RNC Coordinator Audrey Gibson told reporters that security officials took steps to "ban items they could ban" within the perimeter of the RNC, but "in terms of banning weapons in the outer perimeter, that is not within our purview," she said.

During a press briefing Sunday, U.S. Secret Service officials addressed the assassination attempt against former President Donald Trump and the upcoming Republican National Convention following Saturday's shooting.

"This is a national security event and that designation is the highest level that the federal government can determine," RNC coordinator Audrey Gibson said.

"We are confident in the security plans in place for this event and we’re ready to go, it's been an 18-month process," Gibson continued, adding, "We've worked together to develop operational security plans for any and all access of security."

Officials explained that the current Secret Service inner perimeter plan is the "largest inner perimeter that has been part of the convention" and that plans did not change following Saturday's shooting.

Officials said there are no known articulated threats against the RNC.

The man suspected of shooting Donald Trump was employed as a dietary aide at the Bethel Park Skilled Nursing and Rehabilitation Center, according to administrator Marcie Grimm.

Thomas Matthew Crooks "performed his job without concern" and passed a background check, according to Grimm.

Bethel Park Skilled Nursing and Rehabilitation Center said it's cooperating with law enforcement in their investigation.

-ABC News’ Laura Romero and Peter Charalambous