An autonomous security robot became an internet sensation this month when it fell into a fountain at a shopping mall while on patrol. Photos of the toppled-over bot, floating in the fountain, surrounded by bemused humans, eventually surfaced. The singularity will come, but that day is not today, they likely thought, as the robot nicknamed Steve bobbed up and down.

KnightScope, the Mountain View-based robotics company that makes the K5 autonomous robot designed to silently roll through public areas to collect data and assist security guards, concluded its investigation into what happened this week. On Friday, a spokesperson told Inverse that loose bricks were to blame.

“The wheel slip algorithm was unable to detect a certain wheel skid caused by the ‘loose brick surface treatment’ at the facility, rendering the cliff identification system not suitable for that instance,” Stacy Dean Stephens, Vice President of Marketing and Sales at Knightscope, told Inverse.

Welp. Blame the bricks.

KnightScope uses a version of LIDAR, the same technology that’s being developed for some self-driving cars, says the company.

KnightScope’s conclusion lines up with the original theory about the cause of the crash.

Steve’s replacement, nicknamed Rosie after the character from The Jetsons, has been patrolling the Washington Harbour mall in the days since.

The 300-pound KnightScope robots debuted in 2014 and have been rolling since.

This is the second high-profile accident involving a KnightScope robot. In July 2016, the robot ran into a 16-month-old toddler at the Stanford Shopping Center. “The robot hit my son’s head and he fell down facing down on the floor and the robot did not stop and it kept moving forward,” Harwin’s mother, Tiffany Teng, told ABC7 News then.

The robots aren’t sold directly to clients as KnightScope offers a subscription service. A 2014 CNBC story reported that a “basic version” of the robot costed about $6.25 an hour. That price has gone up to $7 an hour, Knightscope tells Inverse, offering this pricing graphic:

KnightScope thanked Washington Harbour, the Washington D.C. mall for their patience and involuntary participation in Steve’s training by providing real-world scenarios beyond what can be tested in the lab.

Steve the robot’s being rebuilt in preparation for its next assignment: ironically, it will be patrolling an aquarium.