Katy Perry's ex-boyfriend Johnny Lewis has been found dead.

The 28-year-old actor - who dated Katy for 18 months until March 2007 - is believed to have killed his 81-year-old landlady Catherine Davis before leaping to his death from his home in Los Angeles yesterday. The upstairs of the building had been ransacked and a cat had also been killed.

"It's a terrible tragedy as far as we're concerned and we're digging into the bottom of it. He appeared to have died from some type of fall, either from the stairway, or from the balcony, or from one of the roofs. The best we're piecing together now is that it appears that some type of altercation occurred inside of the house resulting in the death of the woman. Then this individual ran outside, had an altercation with a couple of neighbors, ran back into the house and by the time we got here, he had fallen or had somehow died on the driveway," said Los Angeles Police Department Spokesman Andrew Smith.

Officers initially responded to a 911 call that a woman was heard screaming. No motive for the killing is yet known.