FBI gains access to Trump shooter's phone in search for motive

July 16 (UPI) -- The FBI said it gained access to the phone of Thomas Matthew Crooks as it searches for a motive for his attempted assassination of former President Donald Trump .

The agency said its technical specialists gained access to Crooks' phone and continued to analyze his electronic devices for clues.

The FBI said it will continue to conduct interviews and will follow up on digital media tips.

The FBI and DHS said in a joint bulletin late Monday that Crooks had received "several packages, including some marked as possibly containing hazardous material," in the past several months based on a review of his shipping history.

He also purchased 50 rounds of ammunition at a gun shop before traveling to the rally.

A search of his home and vehicle had previously found "suspicious devices" that were sent to the FBI's laboratory for evaluation.

The FBI said it continues to believe that Crooks acted alone in the shooting and there is no current public threat.

"The FBI has not identified a motive for the shooter's actions but we are working to determine the sequence of events and the shooter's movement prior to the shooting, collecting and reviewing evidence, conducting interviews and following up on all leads."

In the meantime, the FBI and Homeland Security said they are concerned about the possibilities of retaliatory acts, or "follow-ons."

"We cannot rule out the possibility that some [domestic violent extremist] or other actors may attempt follow-on or retaliatory acts of violence in response to this assassination attempt," the FBI and Homeland Security said in a joint bulletin.

Homeland Security Secretary Alejandro Mayorkas said the department and its agencies will remain vigilant.

"Both President Biden and former president Trump are constantly the subject of threats," Mayorkas said in a White House press briefing on Monday. "We are in a heightened and very dynamic threatened environment.

"United States Secret Service -- we, including the FBI and other partners across the federal government -- take the threat very seriously and adjust security measures as warranted. Maintaining the safety and security of the president, the former president and their campaign events is one of our most vital priorities," Mayorkas said in the briefing .