GALVESTON, Texas -- A mother, father and their two young sons were shot to death early Monday at a Southeast Texas beachfront hotel in what police are investigating as a triple killing followed by a suicide in which the woman was the shooter. CBS affiliate KHOU reports Flor de Maria Pineda, husband Mauricio Morales, their 10-year-old son Mauricio, Jr. and 5-year-old son David all died on the eighth floor of the San Luis hotel in Galveston Monday.

Investigators said Flor shot her husband, two sons then turned the gun on herself.

Galveston police Capt. Josh Schirard said the family from Baytown about 35 miles north of Galveston checked in Sunday evening at the San Luis Resort.

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Police were summoned to the upscale 250-room hotel on the Gulf of Mexico after a guest in a nearby room on the eighth floor called police about 4:30 a.m. and reported popping sounds. Officers entered the locked room and found the man and two boys in bed with apparent gunshot wounds and the woman on the floor, also with a gunshot wound.

When police arrived at the room, the door was dead-bolted from the inside and they heard "faint moaning," KHOU reports.

The woman and one of the children were "unresponsive but still appeared to be alive" and were taken to a hospital where they both died, Schirard said, adding that neither was ever able to speak.

"A motive is unknown at this time, but forensic data collected at the scene indicated the female is believed to be the shooter at this time before apparently taking her own life with a 9 mm handgun found adjacent to her body," Schirard said. "There's no indication or evidence that there are any other persons involved or that there are any other suspects still at large."

Authorities said no issues were apparent before the family checked in, and nothing about the condition of the room indicated there was a struggle.

"My heart goes out to the rest of their family, their extended family, their community and our community, the ones that don't have the training to deal with this and have to be exposed to an event like this," Schirard said.

Psychologists and others who have studied cases of mothers accused of killing their children have said it's not as uncommon as people might believe. But media coverage often focuses on dramatic cases, such as Andrea Yates who was found not guilty by reason of insanity for the 2001 drowning deaths of her five children in Houston.

News of the tragedy stunned neighbors, KHOU reported.

"She was very friendly," neighbor Shirley Davis aid of Flor de Maria Pineda. "She waved at us. Her husband was very friendly. And Daniel and Mauricio they would ride their little bicycles, little tricycles on my driveway and if they saw me outside they would get off those bikes and come hug me. (It) meant more than a lot just to see the little young people so in love with you."