text: A New York City cop checking in on his elderly parents on Friday was horrified to discover them dead along with two other guests in their home. Robert Hugel, who is assigned to the Technical Assistance Response Unit, found the victims, all in their 70s and 80s, just after 3 p.m. at the house in Bellerose in Floral Park, Queens. The New York Post reports that Jerry Hugel, 83, his wife Marianne Hugel, 80, died along with 70-year-old neighbor Gloria Greco, and friend Walter Vondthadden, 76, in an apparent carbon monoxide poisoning, possibly caused by a car left running in a garage. Scroll down for video . Married 60 years: Neighbors say that Jerry and Marrianne Hugel were a happily married couple for 60 years who loved to dance, garden, and observe their German heritage . Cleaning up: Police Department personnel remove one of the bodies from a home where four people were found dead on Friday . It appeared the car was accidentally left running in the garage, but it was unclear for how long, investigators said. Neighbors lined the streets and sidewalks in the suburban neighborhood next to Long Island's Nassau County. Some cried as police officers and firefighters walked around the Cape Cod-style, two-story home. Before police officially identified the victims, neighbor Helga Harter told The Associated Press that the couple was named Jerry Hugel and Marie Hugel, who were in their 80s and had known her for 40 years. 'They were wonderful people,' Harter said through tears as she stood on a street corner, looking at the home. 'They were married for 60 years.' Heartbroken son: Robert Hugel was checking in on his elderly parents on Friday when he found them dead due to apparent carbon monoxide poisoning along with two of their friends . Medical aid: Emergency personnel gather near a home where police say four people were poisoned to death . The Hugels had five children, including son Robert Hugel, a New York Police Department officer who was said to have found his parents lifeless bodies. She described them as a 'great family' very active in the local German community. She last saw them on Wednesday at a Bavarian dancing class they attended together. 'I'm in shock,' Harter said. 'It's the greatest shock of my life.' The Hugels had lived in the home for 40 years, and an elderly woman lived upstairs as their tenant, Harter said. No visible trauma was observed on the victims' bodies, police said. Carbon monoxide, an odorless and colorless gas, is created when some fuels are burned. Hugel was found in the seat of his car in the garage and his wife was found in the room directly next to the garage, reports The New York Post. The scene:  Police stand outside the floral park home where four elderly people were found dead and where to windows are now wide open in an attempt to ventilate the apparent fume filled house . The couple’s friend, age 73, had been seated in the living room and the tenant, who sources said was older than 60, was found on the second floor at the top of the stairs. Neighbors were heartbroken after hearing about the deaths. 'It looks like it was accident, someone just forgot to turn the car off,' a source told The New York Daily News. 'The windows were air-tight, so there was nowhere for the gas to go.' 'It is very surreal,' said Barbara Stoja. 'We knew them for over 35 years. They were very fun people, they were dancers.' 'This is something you see on TV. It is so sad we all know each other to know he is not going to be there anymore.' Stoja said that Jerry Hugel was an avid gardener. 'He was just talking to my husband about planting tomatoes,' she said. Open windows: The four elderly people who died are thought to have been killed by carbon monoxide poisoning and police opened the windows of their home in an attempt to ventilate it . Stunned: Bystanders surround the Floral Park, Queens home where four elderly people died . 'He and my husband compare gardens all the time.' Neighbor Melissa O'Reilly said that the Hugels were avid dancers who loved their German heritage. 'They were such nice people, it’s really sad,' said Melissa O'Reilly, whose parents have lived on the block for three decades. 'They are a really nice family, everyone loves them, just good people, their kids are very nice.' O'Reilly said she knew the family for about 30 years. 'I grew up here, we always called them Mr. and Mrs. Hugel,' O’Reilly said. 'They have lived in that house before my parents moved here, and that was 30 years ago.' The deaths come on the heels of other deadly carbon monoxide incidents that killed at least 10 people on the Eastern Seaboard in recent weeks. A man and his seven children were found dead Monday in a home in Princess Anne, Maryland, where they apparently were poisoned in their sleep while running a generator after a utility cut power to their home on the state's Eastern Shore. The utility, Delmarva Power, said it cut off electricity for safety reasons on March 25, although relatives said the family was behind on its power bills. The family was last seen alive March 28. Saddened: Bystanders gather at the scene where four people were found dead on  Friday, April 10 . On Wednesday, a woman and her 7-year-old daughter were found dead of carbon monoxide poisoning in their home in East Orange, New Jersey. Prosecutors said a utility company had shut off power at the home on Tuesday and a gas generator was being used there without proper ventilation. There was an inoperable carbon monoxide detector in that home, they said. City Councilman Mark Weprin, who represents the area including Floral Park, said he hoped the tragedy would shed light on the importance of having and maintaining carbon monoxide detectors in all homes and apartments. 'My thoughts and prayers go out to the friends and families of the victims,'  he said in an emailed statement. Shaken: Neighbors gather at the scene where four people died due to apparent carbon monoxide poisoning .
target: NYC cop Robert Hugel discovered his parents Jerry, 83 and Marianne Hugel, 80, dead in their Queens home with 'carbon monoxide poisoning'
  The elderly couple was found dead along with neighbor Gloria Greco, 70, and friend Walter Vonthadden, 76 .
  It appeared the car was accidentally left running in the garage, but it was unclear for how long, investigators said .
  Neighbors say the couple were happily married for 60 years .