Photo: The Canadian Press

The FBI received a specific report in January that the suspect in the Florida school shooting could be plotting an attack, but agents failed to investigate the tip, the agency said Friday.

A person who was close to Nikolas Cruz called the FBI's public tip line on Jan. 5 and provided information about Cruz's guns and his erratic behaviour, including his expressed desire to kill people and his disturbing social media posts. The caller was concerned that Cruz could attack a school.

In a statement issued Friday, the agency acknowledged that the tip should have been shared with the FBI's Miami office and investigated, but it was not.

FBI Director Christopher Wray said the agency was still reviewing its missteps. He said he was "committed to getting to the bottom of what happened," as well as assessing the way the FBI responds to information from the public.

"We have spoken with victims and families and deeply regret the additional pain this causes all those affected by this horrific tragedy," Wray said in the statement.

The FBI was also notified about a comment on a YouTube video posted by a "Nikolas Cruz" last year. It investigated the comment but did not determine who made it.

Cruz has been charged with killing 17 people at Marjory Stoneman Douglas High School in Parkland, north of Miami.

Also Friday, mourners gathered for the first funeral for a shooting victim, packing the Star of David chapel to remember 14-year-old Alyssa Alhadeff.