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Mike Fuentes, Associated Press
Police tape stretches through a Grapevine, Texas, apartment complex where police found seven people dead in an apartment on Sunday, Dec. 25, 2011 in Grapevine, Texas. Four women and three men who police believe to be related were found apparently shot to death, and authorities said they believe the shooter is among the dead.

GRAPEVINE, Texas — Authorities in suburban Dallas say they believe a 56-year-old man dressed as Santa Claus killed his estranged wife, his two teenage children and three others on Christmas Day before turning the gun on himself.

Grapevine police spokesman Robert Eberling said Tuesday that detectives believe Aziz Yazdanpanah's marital and financial troubles led him to kill his family.

The Tarrant County, Texas, medical examiner identified the others killed as his wife's sister, her daughter and her husband.

Police responding Sunday morning to a 911 call made without anyone on the line found the seven people inside an apartment near Dallas-Fort Worth International Airport.

It appeared they had been opening presents around their Christmas tree just before the attack.