Last Updated: December 27, 2011 9:27 PM

GRAPEVINE (CBSDFW.COM/AP) – Seven members of a family are dead after a relative showed up at a Grapevine apartment complex on Christmas Day and opened fire before turning the gun on himself.

On Tuesday, the shooter was identified as Azizolah Yazdanpanah, the father of two of the victims.  According to authorities, he was dressed as Santa Claus.

The seven bodies were found late Sunday morning inside of an apartment complex in the 2500 block of Hall-Johnson Road.

Grapevine Police Department spokesman Sgt. Robert Eberling said that first responders arrived to find four adult women and three men dead in a residence at the Lincoln Vineyards apartment complex. The victims all “appear to have gunshot wounds,” Eberling wrote in a news release.

The original 911 came in at about 11:30 a.m. on Christmas Day, from a landline inside the apartment unit where the shooting took place. Eberling initially told reporters that nothing was heard on the other end of the call, but police on Tuesday said that there was the sound of heavy breathing and possibly a faint cry for help. “Officers came out and forced themselves inside,” Eberling said.

Police say it appears Aziz was the one who made the 911 call, based on the location of the phone.

The victims ranged in ages from 14 to 59 and were from different generations of the same family.

The Grapevine Police Department offered details about the incident on Tuesday morning, saying that three of the victims were at the apartment complex when Yazdanpanah showed up — as an invited guest — on Sunday morning. The other three victims arrived afterward.

Sara Zarei, a niece of Yazdanpanah, sent a text shortly after his arrival — at about 11:15 a.m. — in a tone which indicated that nothing was wrong.

Police say she remarked he was trying to suddenly be ‘father of the year’ dressed up as Santa Claus.

The fatal shots were fired at some point between that text and the 911 call — a span of about 15 minutes.  “It seemed like it happened relatively quick, and certainly caught the victims off guard,” said Eberling.

The bodies were resting in the living room and the adjoining kitchen. Two handguns — one with a capacity for 15 rounds and another with a capacity for 10 rounds — were also found near the bodies. Police did not say how many shots were actually fired, but said that the shooter brought both guns into the apartment unit, which implies premeditation.

There was one bullet each left in the guns, a Smith & Wesson 9mm and a Glock 23, police told CBS 11.

Police say it appears some of the victims tried to throw their arms up in an attempt to shield themselves from the bullets.  They say some were hit several times.

The apartment unit was decorated with a tree for the holidays. “It appears they had just celebrated Christmas,” Eberling said. “They had opened their gifts.” Those presents and discarded gift wrap were still on the ground.

“We think he was just inside there celebrating Christmas with the rest of them,” explained Eberling. “Decided, for whatever reason, that’s how he’s going to end things.”

Police are not pursuing any other armed suspects. There were no signs of forced entry and all of the doors and windows were locked from the inside.

Investigators are piecing together a “family history,” Eberling said. He declined to go into specifics.  In a press release, Grapevine Police said Yazdanpanah and his wife Fatemeh Rahmati were separated.

Just after 4:00 p.m. Tuesday the Tarrant County Medical Examiner’s office identified the victims as:

Azizolah Yazdanpanah – 56 – Shooting suspect
Fatemeh Rahmati – 55 – Estranged wife of Azizolah
Nona Yazdanpanah – 19 – Daughter of Azizolah and Fatemeh
Ali Yazdanpanah – 14 – Son of Azizolah and Fatemah
Zohreh Rahmaty – 58 – Sister of Fatemah
Mohamad Hossein Zarei – 59 – Fatemeh’s brother-in-law, Zohreh’s husband
Sara Fatemeh Zarei – 22 – Daughter of Mohamad Zarei, neice of Fatemah

The medical examiner ruled the death of all seven as victims of gunshot wounds.  Grapevine Police said Azizolah’s was self inflicted.

Friends of the family have set up a memorial page on facebook.  According to the page a memorial service is set to be held Wednesday evening at 5:30 at Parr Park in Grapevine.

L.P. Phillips Reports:

Police officers intently searched an SUV parked outside of the apartment late on Sunday evening. The vehicle is registered to Azizolah Yazdanpanah. His Colleyville home was also searched Monday night – as a computer and bags were removed from the residence.

Records show that Azizolah and Fatemeh had financial troubles, and that the home – most recently valued at $336,200 – had been sold in 2010 at a foreclosure auction, but Yazdanpanah was still living there.

The apartment unit is located at the back of the complex, overlooking the athletic fields of Colleyville Heritage High School. Ali was a student at the school. Nona had just graduated. Many of the nearby units were vacant, and even the occupied units were empty on the holiday morning. No neighbors reported hearing the incident.

This is the city’s first homicide since June 2010. “Seven people in one setting in Grapevine, that’s never happened before,” Lt. Todd Dearing said. “Ever.”

The shooting incident remains under investigation.  Funeral arraignments are pending.

(©2011 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)