Relatives of a missing Long Island teen have received mysterious text messages with instructions to search a park – amid fears that the notorious MS-13 gang may be involved in the disappearance.

The manhunt for Louis Germosen, 19, who has been missing since June 28, continued Monday as Nassau County cops investigated the anonymous messages sent Sunday to his cousin, said the victim’s father Luis Germosen.

The first text lists two West Hempstead addresses and is signed with “Good luck God bless,” according to images obtained by the Post

When the recipient asked who the sender was, the person responded by saying: “Check Schodack Pond, Hempstead, NY.”

The second message included an address on Christopher Court in Hempstead, noting that it is “located on the other side of the Pond.”

“Check Both but…Check pond thoroughly,” the message said.

“The police said they are widening the search,” the victim’s father said. “My fear is…I don’t want to think about it. My fear is finding him dead.”

Germosen’s family had previously received a tip that the young man was believed to be spending time with MS-13 members prior to his disappearance.

“I know he wasn’t in gangs but he could have had friends in gangs,” the victim’s father said. “He was probably hanging out with the wrong crowd lately.”

Police could not confirm any information about Germosen’s possible affiliation with MS-13.

Germosen, who was last seen leaving his New Cassel home on June 28, is described as about 5-foot-8 and 180 pounds, police said.

According to his father, the victim’s cell phone was found in Manhattan on Friday.

The gang, also known as Mara Salvatrucha 13, has been operating in Suffolk County for the past decade.

Recently, its violent presence has grown and spread into Nassau County at an alarming rate.

In December, the head of Nassau’s gang unit, Detective Sgt. Michael Marino, told The Post: “They’re more organized, more sophisticated than you think…They have a very distinct structure, a very strong punishment scale for not following certain rules within their gang.’’

“The more I learn about MS-13, the more I felt like I underestimated their organization,” Marino added.