Two handguns, cash and some jewelry were reported stolen from a home on the 100 block of Beatrice Street, police said.
The burglar, or burglars, appear to have entered the home through a window, where an in-window air conditioning unit was installed but not strongly reinforced, according to Mountain View Police Department spokeswoman Shino Tanaka.
The two handguns, a .32 caliber and a 9mm, were taken out of a locked box, she said.
"I would advise that if you have anything like an air conditioning unit, to make sure that the window is secure and boarded up properly, so people can't gain access to the residence," Tanaka said.
Correction: A previous version of this story said that a .23 caliber handgun was taken. In fact, it was a .32 caliber handgun that was taken.