It’s been 26 years since 10-year-old Holly Piirainen vanished.

The Grafton girl was vacationing with her father and other family members at her grandmother’s cottage in Sturbridge on Aug. 5, 1993.

Holly and her brother went off toward a residence in the area of Allen and South Shore Roads in Sturbridge to play with puppies, officials said. The boy returned without his sister.

The Piirainen family on Monday renewed its plea for information related to Holly’s disappearance or killing.

“The Piirainen family has been coping with this tragedy for twenty-six years," Hampden District Attorney Anthony D. Gulluni said in a statement. "Along with Holly’s family, I, members of my office, and the Massachusetts State Police Detectives assigned to the case have never stopped investigating to bring justice to Holly and her family. We continue to ask members of the public who may have any information please contact us.”

Holly’s father, Richard Piirainen, last saw her at 11:45 a.m. Officials said 12:50 p.m. Monday marked the 26-year anniversary of Holly’s disappearance.

Richard Piirainen reported his daughter missing when she did not return. The family immediately went out to look for Holly.

The girl’s sneaker was found on South Shore Road, officials said. A massive search began, conducted by local and state police, sheriff’s departments and units from Connecticut and Rhode Island.

But Holly was not found.

On Oct. 23, 1993, hunters found Holly’s remains in a wooded area off Five Bridge Road in Brimfield, which neighbors Sturbridge and is just miles from where Holly was last seen.

Investigators have named possible suspects in the case, but have never identified Holly’s killer. In 2012, law enforcement said new forensic evidence may help solve the case.

And last year, a tip campaign called “Hope for Holly” was announced with an event in Sturbridge and a vigil.

Holly’s family and authorities have put out calls for information several times as the years passed, marking another anniversary of Holly’s death.

Anyone with information about Holly’s disappearance or killing is asked to call the Massachusetts State Police Detective Unit assigned to the Hampden district attorney’s Office 413-505-5993. Tipsters can also use text-a-tip by texting the word CRIMES (2-7-4-6-3-7) and typing the word “solve” into the body of the message followed by a tip.