In a troubling revelation, local law enforcement alerted the Secret Service about their lack of resources to station a patrol car outside a key building where a gunman later positioned himself and shot at former President Donald Trump during a rally on Saturday. Richard Goldinger, the district attorney in Butler County, Pennsylvania, where the rally took place, confirmed that the Secret Service was informed of the manpower issue. The warning from local law enforcement has added to questions surrounding the adequacy of security measures for the high-stakes presidential campaign visit.

According to a Secret Service official briefed on the incident, positioning an officer outside the building was considered crucial for protecting against the potential threat of a shooter on high ground with a clear line of sight on the president or other senior officials. The building, owned by Agr International, was just outside the security perimeter set for the rally.

The investigation is still underway to determine how the 20-year-old gunman, identified as Thomas Matthew Crooks of Bethel Park, Pennsylvania, reached the roof of the building. Crooks used an AR-style rifle legally purchased by his father in 2013. It remains unclear how many other firearms the father currently possesses. Authorities discovered a remote trigger device on the roof with Crooks after he was shot.

The serious security failure at the rally, resulting in injuries to Trump and others, has prompted federal authorities to launch multiple investigations. The FBI is leading the criminal investigation, Congress is planning to hold hearings, and President Joe Biden has called for an independent probe into the shooting and overall security situation.

In response to the incident, the House Oversight Committee Chairman James Comer (R-Ky.) subpoenaed U.S. Secret Service Director Kimberly Cheatle, demanding her testimony at a hearing next week. Comer questioned Cheatle's ability to lead the Secret Service due to the agency's lack of transparency and failure to cooperate with the committee.

Cheatle, in an interview with ABC News, took responsibility for the security failures that led to the shooting, but also emphasized that the Secret Service relied on local law enforcement for areas outside the security perimeter. She explained that the decision was made to secure the building from inside, citing safety concerns on the sloped roof.

As the investigation continues, questions about the Secret Service's planning, strategy, and response to the attack loom large. The agency is under pressure to address what analysts have termed a major security failure.

The FBI has named Thomas Matthew Crooks as the gunman responsible for the shooting. The Washington Post has utilized videos and photos to construct a 3D model of the shooting site, revealing that Secret Service countersniper teams may have initially struggled to spot the shooter due to the roof's slanted sides and nearby trees.

This is an ongoing story, and further updates will be provided.