"We made an arrest [on Saturday] and a 20-year-old female has been charged with assault. She has been co-operating with us," Mr Lynch said. "There are a lot of inquiries that we are now conducting, including a post-mortem examination and a thorough investigation of the scene."
Police could not comment further as the woman was due to appear in Hastings District Court tomorrow.
The arrested female lived with the victim and Hawke's Bay Today understands they may have been romantically involved.
A Facebook update from Friday night listed the pair as "engaged" but it was later removed. Police cordoned off the house and placed a patrol car on guard in the early hours of Saturday morning. A team of forensic investigators from Wellington arrived yesterday to examine the scene.
Mr Lynch said a forensic scene examination of the house was likely to be completed today and police were evaluating early post-mortem results.
Police were also working through a large number of interviews with people who were at the house at the time of the incident.
Tenants of the four-bedroom weatherboard bungalow were being questioned by police and had not been allowed back into the flat.
A neighbour told Hawke's Bay Today the housemates were well known for their "all weekend parties".
"It's a nightmare. I was down there last weekend and the weekend before, telling them to turn the music down. It's also the noise from their cars out on the street.
"There is just party after party after party."
"Some of the ladies across the road are in their 80s. We just want this to stop, we just want a quiet street."
Though the group of tenants had lived at the address only for about two months, police and the landlady had been called numerous times by residents fed up with their rowdy behaviour, the neighbour said.
"A while ago they were all out on the street in the morning, drunk, next to a black van. There were cans and bottles all on the road." The neighbour said people had been urinating on one lady's lawn.
"Police showed up a bit later ... they must have made the rest of them get out of bed and clean everything up."
The neighbour was not aware of a woman living in the house but had noticed a new car parked in the driveway for the past month.
She also noted the often-troublesome flat was relatively quiet on the evening of the incident. "I just crashed, I didn't hear anything and usually I would if there was a party going on. I'm still getting my head around the fact that someone has died."