Thieves who stole computers and valuables from a charity for victims of sexual violence have had a change of heart and returned the goods.

They broke into the offices of the Sexual Assault Services Centre in San Bernadino County, California one evening after immobilising the burglar alarm and crawling on the floor to evade motion detectors.

When centre director Candy Stallings arrived after being contacted by police she discovered the office had been ransacked and computer equipment was missing.

"Our office is really secure," she told CBS Los Angeles. "We have the best locks but they still managed to find a way in."

However later that day police called her to say the thieves had returned all of the stolen items.

"All my stuff was in front of the door," she said. "There was a shopping cart, and there were the PCs that were taken and the laptop; everything was there."

When she opened the laptop, she discovered a hand written note, apologising for stealing the equipment.

"We had no idea what we were takeing (sic)," it read. "Here your (sic) stuff back. We hope that you guys can continue to make a difference in peoples (sic) live. God bless."

"We were all pretty shocked," said Ms Stallings. "You've got to be kidding me. I was in disbelief. I got chills. I got very emotional."

"This is the first time in my career I have seen the return of stolen items," San Bernardino Police Lt Paul Williams said.

"It appears the guilt of taking the property caused the return of the items."