A determined daughter tracked down the thug suspected of killing her father 26 years ago by conducting an online manhunt.

Joselyn Martinez, 36, an aspiring actress from The Bronx, spent years trying to find the man who shot her father in front of his Bronx restaurant in November 1986 — when she was only 9.

On Thursday, police in Miami finally arrested Justo Santos, 43, after help from the NYPD — and the amateur online sleuth.

“I always kept the name in mind,” Martinez told The Post early this morning.

“After so many years of not being caught, it wasn’t a reality to me anymore.”

She said she had kept Santos’ wanted posters as a reminder of her father’s killer.

And when she started to use social media about 10 years ago, she kept an eye out for the man she had been looking for.

“In 2004, when I started using MySpace, that’s when I got into using social media” to track him down, Martinez said.

Her mother was ecstatic at the news last night.

“She did a good job, my daughter,” said Idalia Martinez, 62.

The proud mom said her daughter helped find the suspect after years of heartache over the loss of her loving father.

“He ruined my life,” Idalia Martinez said about Santos this morning. “He ruined the life of my daughter. She suffers without him every day.”

Santos is being held at a detention center in Miami while cold-case detectives from the NYPD travel to Florida to extradite him.

The suspect will be taken back to New York and face the charges related to the 1986 killing.

José “George” Martinez was shot and killed in front of his Dominican restaurant in the Inwood section of Manhattan.

The suspect was identified by police after the attack, but managed to escape the NYPD and get out of New York City.

“He killed my husband,” Idalia Martinez told The Post.

“He’s responsible.”

After an exhaustive Internet search, Joselyn found a match for the suspect and then called detectives at the 34th Precinct in The Bronx.

NYPD detectives then worked with Miami police to find Santos, who was booked on murder charges on Friday in Florida.

Additional reporting by Larry Celona

