Authorities have said that the Florida State University shooting suspect, killed by police on Thursday, had recently sent packages to eight of his friends before he opened fire in the school’s library.

USA Today reported that eight people who knew the suspected gunman Myron May, are awaiting packages from him. They were each instructed to call police once the parcels arrive.

Joe Paul of Alexandria, Virginia, told WBS-TV that May alerted the group that they would be receiving a package from him. Paul said he was notified by the U.S. Postal Inspector that his package had arrived at the post office. The inspector informed him they checked it for any hazardous materials and will release it to him at some point.

“People were a little afraid,” Paul said of those expecting a package from the suspect. “Why did he choose us? That's a lingering question. Why us?"

A law enforcement official said that another package from May had arrived in Texas and it contained the suspect’s journals and videos, which the FBI is now investigating.

Police said that on Thursday May, a former FSU graduate, was allegedly armed with a semi-automatic handgun when he walked into the Tallahassee's Strozier Library and started shooting.

Two students and one library employee were shot.

May’s friends said the suspect had long struggled with mental health issues.