The suspected gunman who attempted to assassinate former President Donald Trump at his campaign rally Saturday purchased 50 rounds of ammunition ahead of the event, according to a bulletin from the Department of Homeland Security and the FBI Monday.

Thomas Matthew Crooks purchased the rounds from a gun and ammunition shop in Bethel Park, Pennsylvania, according to officials.

The bulletin notes that two improvised explosive devices were found in the shooter's car and one at his home.

"Over the last several months, Crooks received several packages, including some marked as possibly containing hazardous material, according to a review of his shipping history," officials wrote.

Officials also warn of future "follow-on or retaliatory acts of violence in response to this assassination attempt."

"We cannot rule out the possibility that some DVEs (Domestic violent extremists) or other actors may attempt follow-on or retaliatory acts of violence in response to this assassination attempt."

-ABC News' Mike Levine

Thomas Matthew Crooks, the suspected gunman in the deadly campaign rally shooting Saturday, did not have any disciplinary problems while attending community college and graduated with "high honors," the school said in a statement Monday.

Crooks, 20, graduated from Community College of Allegheny County (CCAC) in May of this year and majored in Engineering Science, according to the college.

"This individual graduated from CCAC with high honors on May 16, 2024, and was conferred an Associate in Science degree," spokesperson Dena Rose Buzila said in a statement. "In addition, based upon our preliminary review, CCAC has no records relating to any disciplinary, student conduct or security-related incidents involving the identified individual."

Eric Trump said there is "no question" that a Trump family member will attend the funeral of Corey Comperatore, who was shot and killed at the campaign rally on Saturday.

During an interview with Fox News on Monday night at the Republican National Convention, Eric called Comperatore's death "unthinkable," adding, "This is a person who loved Donald Trump, his family. He jumped on his children. It's unthinkable what happened there."

Comperatore, 50, was a firefighter and a father of two daughters, Pennsylvania Gov. Josh Shapiro said Sunday. He was from Sarver, Pennsylvania.

Comperatore "died a hero" when he "dove on his family" to protect them from the gunfire during the rally, his wife said, according to Shapiro.

Eric Trump said that the GoFundMe page created for Comperatore's family was close to reaching $5 million.

In his first interview since Donald Trump was shot at a rally Saturday, Eric Trump was asked if U.S. Secret Service Director Kimberly Cheatle should stay in her position.

"The head [of the Secret Service]? No, they should have had more resources," Trump said.

"Listen, at the end of the day, we can't get past the fact that somebody should not have gotten on a roof 130 yards away from the president of the United States -- you know, ex-president of the United States, and soon to be president of the United States, with a high power rifle; that's inexcusable," Trump said.

Speaking with ABC News Chief Justice Correspondent Pierre Thomas, Cheatle called the shooting "unacceptable," saying, "it's something that shouldn't happen again."

In the days since the attack, Cheatle and the Secret Service have faced heightening scrutiny for failing to prevent the incident from happening, and even calls from some to resign.

Cheatle said she would not resign from her role.