A man at the centre of what police are calling an “unexplained” death at a Christchurch house was a gun-collecting pensioner.

Officers were called to the residential address on Eastern Terrace in Beckenham at about 8.20am on Saturday, where they found the man dead.

Today, a specialist search team scoured the property for clues in an investigation to determine what happened in the lead-up to the event and how the man may have died.

The man’s Facebook page features many posts showing specialist rifles and pistols, as well as military models.

In the window of the man’s home, a stack of items could be seen, including a box with ‘Crosman Air Guns’ written on it.

A Crosman-branded gun was one of the many he had previously posted about online.

Police have described the case as “perplexing” and have called on the public for information.

Police specialist search teams were seen at the property on Monday. Photo / George Heard

One neighbour said the death of the man “was very bizarre”.

Police said they are particularly focused on tracing the man’s movements over the past two weeks.

Police say the circumstances of the man’s death remain unclear. Photo / George Heard

“We are committed to establishing the full circumstances surrounding this man’s death,” Detective Senior Sergeant Daniel Overend said.

“This is a perplexing case, and we are keeping an open mind as we work through a number of inquiries.”

Police specialist search teams were seen at the property on Monday. Photo / George Heard

As part of the investigation, police have been conducting an area canvas of the Eastern Terrace neighbourhood.

A book about guns seen in the window of the property. Photo / George Heard

Police have appealed to the public for any information that may assist and to identify anyone who may have seen or interacted with the man in recent weeks.