Friends thought a heart attack felled him at a party. It was a bullet. But from where?

It was a Saturday night and Yemil Arguelles was visiting a friend a short drive from his Kendale Lakes home for a holiday party, when he started grabbing his chest.

At first, police said, people attending the gathering thought Arguelles was suffering a heart attack. He wasn’t. A bullet pierced his chest and the married father of two died a short while later at the hospital.

“The people just looked at him and he was holding his chest,” said Miami-Dade police Detective Argemis Colome. “He was just a regular guy at a party.”

Police quickly determined that Arguelles wasn’t shot by anyone at the party. They believe the bullet came from across the lake that abuts the grassy backyard of the single, two-story home where Arguelles, 40, was sitting when he was shot.

Residents who live on the other side of the lake said police were there this weekend asking questions and taking notes. None of them on Monday were willing to speak on the record. Miami Herald news partner CBS 4 said several residents across the lake said they heard gunshots.

If police have clues or a motive, they aren’t sharing it. They haven’t released the type of weapon used in the shooting death of Arguelles because it’s likely only the shooter knows that information. At this point, they’re not even certain if the shooter knows someone was killed by the bullet or Arguelles was killed by an accidental discharge.

No one was home late Monday afternoon at the house where the shooting occurred in the 7000 block of Southwest 159th Place. The front of the tan lakeside home was covered with Christmas ornaments, a wreath on its front door, bows on walls, an inflated holiday decoration lying flat on its front lawn.

Police said it was just past 11 p.m. when Arguelles, seated in the backyard, starting grabbing at his chest. He was with his wife. Miami-Dade Fire Rescue transported Arguelles to Kendall Regional Medical Center, where he succumbed to his injury. Police are asking the community for help in finding the shooter.

On Monday afternoon family and friends gathered at his home, about 20 blocks from where Arguelles was shot. The street and driveway were packed with vehicles. State records show Arguelles owned a company called Safety Tech Auto Glass, which he ran out of his home.

Jorge Arguelles said his brother was married with two children. Asked if family would speak about his brother’s life, Jorge Arguelles said he didn’t want to and that his brother’s wife was in “too much pain” to speak to the media.

“The police said they’re going to have a press conference,” Jorge Arguelles said. “So speaking to you is not going to make any difference right now.”