One man gunned down. Another found dead in his living room. And a third body discovered floating in a popular swimming spot.

The suspicious deaths of three Waikato men in the past two weeks have prompted three homicide investigations.

Armed police have shut down areas of suburban Hamilton to negotiate with people of interest in connection with the serious crimes.

And the police's Eagle helicopter has been used to search residential streets for a vehicle believed linked to another of the deaths.

Then, late on Friday night, someone set a fire inside a house where three people were shot - one fatally.

As speculation and rumour over the deaths run rife through the community, police are remaining tight-lipped over possible suspects or motives behind the individual killings.

No arrests have been made.

The latest death of Mitchell Curtis Rehua Paterson - a Ngāruawāhia local whose body was found in the water at McLaren Falls, near Tauranga - led police to a home in central Hamilton city.

Armed guards were posted outside the modest townhouse in Mill Lane, Whitiora, as detectives searched the home.

Patterson's Facebook page shows connections to several gangs and includes video of the Greasy Dogs motorcycle club.

A friend posted online that Paterson was "always a good fella to me, always had some crack-up times".

Sonny Rutene said he was speechless at Paterson's death.

"Was only talking to you last week, knew something was up because u normally message me on a Thursday or Friday morning, you weren't answering your phone.

"You was a good guy when u needed to be. You always there. It's hard to know that the last time time I seen you was the last time."

The death of the 26 year old comes six days after three people were shot at a home in Matthews Crescent in Melville.

Robert Nelson was killed when at least one armed intruder burst into his girlfriend Kahlee Marfell's family home and began firing.

Marfell, 20, remains in Waikato Hospital recovering from surgery for gunshot wounds.

Another 17-year-old man took shots to his head - above his eye - and body. He was transferred from Waikato Hospital to Auckland City Hospital.

A fourth person was home at the time and was uninjured.

The early morning shooting at the house of Marfell's father - a senior Mongrel Mob member - sent shockwaves through the community.

Nelson, a trainee chef at Keystone bar in downtown Hamilton, was farewelled at a service in Newstead on Saturday. Police said there were no problems at the funeral.

But a day earlier, police were called back to the shooting scene after a suspicious fire was lit inside the now empty brick home.

A car was seen leaving the scene.

Police have revealed no details about who they believe is behind the shooting or whether there are any potential links between the shooting and Paterson's death.

Meanwhile, investigations into the suspicious death of a Huntly man Wayne Noda are continuing.

The 48 year old was found dead in the living area of his Berrymans Access Road home, behind Huntly Power station, on June 30.

He died of injuries inflicted during an assault.

Detective Senior Sergeant Ross Patterson said on Monday that police were continuing to look for a 2001 Nissan Skyline, registration KAM195, in connection with his death.

A police Eagle helicopter had circled areas over Dinsdale on Monday looking for the vehicle.

Police were still keen to hear from anyone who may have seen the vehicle in or around Hamilton. Witnesses can contact the Operation Tailor team at Huntly Police Station on (07) 828 7650.

If people have information about any of the investigations, they can contact Hamilton police on 07 858 6200, or phone Crimestoppers anonymously on 0800 555 111.

- Stuff/Phillpa Yalden.