Jonathan Tran, the man accused of hopping White House fences last weekend, was reported to be strolling around the grounds for more than 15 minutes before Secret Service was able to apprehend him, according to reports. The Secret Service is conducting a Mission Assurance Review to investigate how Tran, despite setting off several alarms, was not quickly captured.

A Secret Service source told us that Tran was able to scale multiple fences before making his way across the grounds and landing mere few steps from the main entrance. He was even able to bypass the East Wing Secret Service post in the process. The whole situation, as described by CNN, sounds like an intricate game of cat and mouse. It also highlights the vulnerabilities of President Trump’s security detail:

The source said Tran activated an alarm sensor, but was hiding behind a pillar of the East Wing entrance. The source said Tran then jumped a low wall before traversing along East Wing. Several sensors went off, but it is unclear if they were properly investigated. A variety of detection systems ring the White House complex in overlapping zones. The systems primarily rely on infrared and microwave technology but can be subject to malfunction or false activation.

However, while Donald Trump commended the Secret Service for how they dealt with the manner, some aren’t so congratulatory, including Chairman of the House Oversight Committee Rep. Jason Chaffetz. The Utah Congressman reportedly sent a letter to acting Secret Service Director William J. Callahan on Friday. The committee will be digging into how Tran bypassed security, and Chaffetz said, “If true, these allegations raise questions about whether the agency’s security protocols are adequate.”