Police investigating the “random” stabbing of a 73-year-old man on the doorstep of his home in Devon are trying to establish whether the suspected suicide of a driver six miles away is linked.

The stabbing victim died after he was found with multiple wounds in a cul-de-sac in Kingsteignton, a small town near Newton Abbot, on Sunday evening. On Monday morning, Devon and Cornwall police were told that another man had been found dead in a car at a coastal beauty spot a few minutes’ drive away.

Det Supt Mike West, the force’s head of major crime, said on Monday: “We have launched a major investigation following [Sunday’s] murder. Late this morning we were also made aware of a body of a man found deceased within a car near Labrador Bay, Shaldon.

“This death is not currently being treated as suspicious and we are responding to the incident as a suspected suicide. The police are currently investigating the link between this and the incident in Chockland Road, Kingsteignton.

“At this time we are appealing for witnesses and we would like to hear from anyone who was in the vicinity of Chockland Road between midday 9 June and midnight. We are also keen to hear from anyone who was in the vicinity of Labrador Bay in Shaldon and saw a Blue Skoda Fabia between midday 9 June and 11am Monday 10 June.”

West added: “There is every indication at the moment, in the evidence collated to date, to say it is a random attack.”

The stabbing victim, who has not been named, was found at about 9.20pm on Sunday and taken to hospital in Torbay, where he was pronounced dead.

Wendy Roberts, who lives near the house where the stabbing took place, said she saw a lot of blue lights and armed police. “My house backs on to the house where the incident took place. You never expect anything like that around here,” she said. “The worrying thing is that no one has been arrested. When I went out this morning, I told my daughter to keep all the doors locked and not to answer the door.”

Another neighbour, Martin Alford, said he heard a woman outside screaming after the incident took place. “We saw all the blue lights, then a big police Range Rover pulled up outside, armed police got out with their guns, and a police officer came and knocked on our door and asked if we had seen or heard anything.”

Tributes were paid to the victim. One neighbour said: “This is a close-knit community and I can’t understand why this has happened. He had not long retired, he was not the sort of person who would have enemies, and it is just so, so tragic. He was just an all-round nice guy.”

Another neighbour said: “He was just a lovely, lovely bloke and a really good neighbour. It is a terrible, terrible thing that has happened. We are all in deep shock. I knew him and his wife very well. We are all friends around here and it is just devastating.”