A Canadian experiment to test the kindness of strangers has provided an unsettling result.

After making the trek from Boston to Philadelphia, hitchBOT — a hitchhiking robot that had captured the hearts of fans worldwide — is no more. An unknown assailant damaged the robot beyond repair on Saturday in Philadelphia, according to its creators.

Prior to meeting its demise just two weeks after hitting the road in the U.S., hitchBOT made it across Canada and through much of western Europe.

Oh dear, my body was damaged, but I live on with all my friends. Sometimes bad things happen to good robots! #hitchBOTinUSA — hitchBOT (@hitchBOT) August 1, 2015

The Canadian researchers who created hitchBOT as a social experiment told the Associated Press that they received an image of the vandalized robot Saturday, but cannot track its location because the battery is dead.

They said they don't know who destroyed it or why, but co-creator Frauke Zeller said the many children who adored the robot have been left heartbroken.

hitchBOT is immobile on its own, so it gets from place to place by relying on the kindness of strangers. Or it doesn't.

Its American journey started in Marblehead, Massachusetts on July 17 with its thumb raised skyward, a grin on its digital face and tape wrapped around its cylindrical head that read "San Francisco or bust."

The robot bounced around the Boston area, attended a Red Sox game and was even briefly taken to sea. But tragically, hitchBOT never made it off the East Coast.

hitchBOT was designed to be a talking travel companion and could toss out factoids and carry limited conversation. A GPS in the robot tracked its location, and a camera snapped photos about every 20 minutes to document its adventures.

My trip must come to an end for now, but my love for humans will never fade. Thanks friends: http://t.co/DabYmi6OxH pic.twitter.com/sJPVSxeawg — hitchBOT (@hitchBOT) August 1, 2015

During past hitchhiking trips, the robot attended a comic convention and a wedding, and had its portrait painted in the Netherlands. It once spent a week with a heavy metal band.

Farewell, hitchBOT. We hardly knew ye.

UPDATE: Aug. 3, 3:05 p.m.

YouTube star Jesse Wellens claims to have obtained surveillance footage of an unknown man destroying hitchBOT.

I got the surveillance footage!!! @hitchBOT going thru it now! #PvPNews — Jesse Wellens (@Jessewelle) August 3, 2015

Wellens sent the video footage out on Snapchat, and a follower then shared the quick clip on Twitter:

Meanwhile, one of hitchBOT's creators Frauke Zeller said that the outpouring since Saturday has been very positive, with many people offering to help rebuild the robot. (And hopefully make it faster, and stronger.)

“We were taken quite by surprise because it’s been going so well so far,” she told The Canadian Press. “We don’t really know what to do, so we have to sit down with the whole team and really see where we are and what can be done.”

And she said she doesn't think the city of brotherly love is to blame.

“I’m sure it could’ve happened anywhere,” Zeller said. “We don’t really think it has anything to do with Philadelphia.”

Additional reporting by the Associated Press