SAN DIEGO (CBS) — Another family murder-suicide has claimed the lives of two teens and a father in San Diego.

A Chula Vista man shot and killed his two sons, 13 and 15, set his home on fire, and then turned the gun on himself, police said Tuesday.

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KNX 1070’s Tom Reopelle reports several suicide notes were recovered inside the house, but investigators said that a motive has not yet been determined.

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Police said the father worked as a local attorney.

The shooting marks the county’s third family murder-suicide in the past month, with two in Chula Vista and one in San Diego.

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Six of the total victims have been children under the age of 16.