MIAMI GARDENS (CBS4) - More than a year after a deadly robbery of a clothing store owner Miami Gardens Police say they have found the killer.

Police say DNA evidence led them to Serge Burrows, who is already serving more than 4 years in prison for a bank robbery. Burrows is accused of shooting Salim Ullah at Fast Cash and Urban Wear in February 2011.

The news of the arrest came as a relief to Ullah's wife and two small children.

"This is great news," Sabiha Sultana told CBS 4's Carey Codd. "Now I am safe."

But Sultana and her daughters -- ages 5 & 4 -- are still in pain. They weep at the depth of their loss, remembering a father who doted on his daughters and provided for his family. In her grief, Sabiha wonders what kind of future lies ahead for them.

"Our life is done," she said, as her daughters cried. "They're crying for their dad. We don't have any future."

Surveillance cameras rolled inside the clothing store last year showing an armed man walk in while Ullah swept the floors. He quickly hustled his wife to safety then struggled with the gunman.

The gun went off.

While Ullah lay wounded on the floor, surveillance video shows the robber trying to open the register -- even shooting at it -- to no avail.

After the thief flees, Sabiha is seen trying to comfort her husband.

"My husband say two things," she explained. "One is 'Take care of my two children' and 'We will see you in heaven.'

"I ask him, 'You feel pain?' He said, 'No, wife. I feel hot.'"

A short time later, Ullah was dead.

For months police searched for his killer.

Investigators say DNA found under Ullah's fingernails matched Burrows. Burrows is serving more than 4 years in a North Florida prison for a Hialeah bank robbery that happened in June 2011 -- 4 months after the deadly shooting.

Police say Burrows is charged with first degree murder for killing Ullah.

Miami Gardens Police Captain Ralph Suarez said this case required painstaking work by detectives and crime scene investigators. Suarez said there is a message for criminals.

"We are gonna find you one way or another," Suarez said. "It might take longer than a year but we are going to find you."

Police say Burrows will eventually be brought to Miami to face the murder charge.

Ullah's eldest daughter, Wafeeqa, wanted to speak about her father. She said simply, "My daddy was so good."

Her sister, Yusra, still has trouble sleeping at night. Her mother believes it's because she misses resting her head on her father's chest.

For this family that has lost so much -- a loving husband, a giving father -- they might lose even more because of this tragedy. Sabiha said the family's modest townhouse is in foreclosure. Sabiha said she has started working as a substitute teacher and is trying to provide, but it's hard.

Despite the worries and pain, there are smiles as a determined mother tries to cope with loss and provide a foundation for her daughters.

"I just need my two children good future," Sabiha said.

Sabiha Sultana still needs help. If you'd like to assist her, contact Neighbors 4 Neighbors at (305) 597-4404.