NEW YORK (CBSNewYork/AP) — Nearly 15 years after the Sept. 11 terror attacks, an FDNY chief who died in the World Trade Center collapse was honored with a funeral and final farewell.

As CBS2’s Steve Langford reported, Theresa Stack was joined on what would have been her 49th wedding anniversary by family friends and the full force of the FDNY. They gathered to bid farewell, finally, to FDNY Safety Battalion Chief Lawrence Stack.

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Stack was investigating the June 2001 Father’s Day fire that left three firefighters dead when he raced to the north tower on 9/11. Stack was last seen helping a businessman from Iowa who was injured in the early moments of the attack.

“They were helping a civilian out and Larry was the last one down there and he never got out,” retired FDNY Firefighter Danny Prince said.

Stack’s remains were never found, only his turnout coat.

“He’s among the 127 members of the department who were never recovered from ground zero,” said FDNY Commissioner Daniel Nigro.

But recently, the Stack family was notified of a blood sample the late chief had donated before he was killed, enough remains to hold a funeral, full departmental honors by the FDNY.

But Stack’s family recently discovered two vials of blood that the 58-year-old had donated during a bone marrow drive for a child with cancer just weeks before he died.

The vials were located in Minnesota and returned to the family.

On Friday, after a funeral mass was held in Stack’s hometown of Saint James in Suffolk County. The casket bearing the blood vials was placed on top of a ceremonial fire truck, flanked by Stack’s firefighter sons – Michael and Brian.

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The strains of bagpipes filled the air as the procession departed for Calverton National Cemetery, where the vials were buried in recognition of Stack’s service in the U.S. Navy.

“This is all about never forgetting — 15 years later, never forget,” said firefighter Ray Pfeiffer.

Michael Stack told the overflow crowd of his father’s last phone call to their mother on Sept. 11, 2001.

“My dad called my mom as they headed over the Brooklyn Bridge to tell her he loved her, and not to make dinner that night,” Michael Stack said.

Michael Stack also described his father’s heroic actions.

“My father stayed with the injured man, probably telling him all the while, ‘Everything’s going to be all right,’” Michael Stack said. “The North Tower collapsed. He never left that man.”

Mayor Bill de Blasio also attended the service, along with thousands of firefighters.

Mourners noted the significance of the funeral falling on what would have been Stack’s wedding anniversary.

“I know (Theresa) wanted to have something of Larry, no matter what it was,” Prince said. “I’m hoping and praying that she will get what she deserves — having a place to sit with Larry because they were a great couple.”

Chief Stack served the department for 33 years. His father was a 38-year veteran of the FDNY and his brother served 26 years.

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