Two local law enforcement officers stationed in the complex of buildings where a gunman opened fire at former President Donald Trump left to go search for the man before the shooting, the head of Pennsylvania State Police said Tuesday, raising questions about whether a key post was left unattended as the shooter climbed onto a roof.

Pennsylvania State Police Col. Christopher Paris told a congressional committee that two Butler County Emergency Services Unit officers were stationed at a second–floor window in the complex of buildings that form AGR International Inc. They spotted Thomas Matthew Crooks acting suspiciously on the ground and left their post to look for him along with other law enforcement officers, he said.

Paris said he didn’t know whether officers would have been able to see Crooks climbing onto the roof of an adjacent building had they remained at the window. A video taken by a lawmaker who visited the shooting site on Monday shows a second–story window of the building had a clear view of the roof where Crooks opened fire; it was unclear if the video showed the window where the officers had been stationed.

The Pennsylvania State Police commissioner’s testimony before the House Homeland Security Committee provides new insight into security preparations for the Trump rally in Butler, Pennsylvania on July 13, but raises further questions about law enforcement’s decisions before Crooks opened fire.

Butler County District Attorney Richard Goldinger, who oversees the emergency services unit, didn’t immediately respond to a text message Tuesday from The Associated Press. A Secret Service spokesperson didn’t respond to questions from the AP, including who gave the command for those officers to leave their post.

The revelation comes amid growing questions about a multitude of security failures that allowed the 20–year–old gunman to get onto the roof and fire eight shots with an AR–style rifle into the crowd shortly after Trump began speaking. One spectator was killed and two others were injured. Trump suffered an ear injury but was not seriously hurt.

Secret Service Director Kimberly Cheatle resigned earlier Tuesday, a day after she was berated for hours by Democrats and Republicans over the agency’s failure to protect the Republican presidential nominee. Cheatle told lawmakers on the House Oversight and Accountability Committee on Monday that the assassination attempt was the Secret Service’s “most significant operational failure” in decades.

The Homeland Security Committee also had asked Cheatle to testify but lawmakers said she refused. Cheatle’s name was on a card on a table in front of an empty chair during the hearing, which began shortly before her decision to step down became public.