Carmen police scan drain

Manson TCLM, which employs the former partner of Carmen Thomas, is building an office block at the site detectives are focusing on. Photo / Greg Bowker

Police searching for the body of Auckland mother Carmen Thomas yesterday lowered a high-tech camera into a drainage system on a central Auckland construction site.

And they confirmed they were speaking to several people who were helping with their inquiries - some of whom were "of more interest than others".

In a series of developments yesterday in the 12-week murder mystery, officers arrived about 7am at the Victoria St construction site being developed by the firm Manson TCLM.

A worker at the site, who did not want to be named, told NZPA that police had last week drilled a hole in a concreted area there.

Yesterday, officers returned with a camera, which they lowered down the hole.

Detectives want to dig up recently laid concrete, and have reportedly put this request to Manson. The firm has said it is co-operating with the police.

It was also reported last night that police had been checking timesheets of workers at the site and that they had asked neighbouring businesses for CCTV footage from around the time of July 1.

Ms Thomas' former partner, Brad Callaghan - the father of their 5-year-old son, Jack - works for Manson.

The property development firm has two office projects in Victoria St. One is at 167-191 - the new Telecom corporate headquarters due to be finished next year.

The other, at 162, is the site the camera was used at yesterday.

Police spokeswoman Noreen Hegarty would not confirm that staff had put a camera down a hole.

She said the investigation into Ms Thomas' disappearance - and her death and disposal - was progressing.

Ms Hegarty said police were speaking to several people who were helping with their inquiries, some of whom were "of more interest than others".

"Details around operational activities will not be publicly discussed or elaborated on."

The office block development site at 162 Victoria St was busy yesterday with three diggers working and new piles being drilled into the ground. Workmen were also removing part of an old wall.

Businesses near the development told the Herald police spoke to them two weeks after Ms Thomas was reported missing.

Pejman "PJ" Asar from Right Cuts said between 15 and 20 officers canvassed his part of Victoria St but police had not been back since then to talk to businesses there.

He said officers showed him a photo of a car which he later learned from news reports belonged to Ms Thomas.

"They said to me that it was the last time that she was seen - in this area," Mr Asar said.

Hyun Ju Lee, manager of Victoria Sushi, said police visited the busy lunchtime cafe to talk to staff on the sushi line.

"They were checking out if we had seen the car," Ms Lee said.

Nearby at Hertz, Deven Naicker said staff there had also been spoken to. He said they were asked if they had seen Ms Thomas around Victoria St.

Les Mills gym manager Jackie Marshall said police had interviewed staff "a long time ago". TVNZ reported last night that the gym had been asked for CCTV footage showing its carpark.

Police confirmed at the weekend that they had found Ms Thomas' recycling wheelie bin on September 1. It had been missing from her Remuera home.

The bin was forensically tested, as was her car, which was found with blood inside on a Hamilton street in July.

There have been no confirmed sightings of Ms Thomas since she visited the Greenlane Countdown on June 27.

Her bank accounts have not been touched, and she has not contacted family or friends.

Police said last month that she had been murdered.

Ms Hegarty said officers were still intent on finding Ms Thomas and information about how she died.

"We will follow any leads or information that we believe could assist us with that."

The Case

June 27: Last confirmed sighting of Ms Thomas, at Greenlane Countdown about 7.10pm. Last day her bank accounts were touched.

June 28: Message sent from her Facebook account at 8.14pm.

July 1: Police have been seeking CCTV footage from central Auckland around this date.

July 3: Text sent from her phone to her boss at a Pakuranga men's club.

July 7 or 8: It is believed Ms Thomas' car was driven from Auckland to Hamilton.

July 13: Car towed and Ms Thomas is reported missing after failing to collect her son.

Sept 1: Ms Thomas' wheelie bin is found by police.

Yesterday: Police put a camera down a hole at a worksite on Victoria St in the Auckland central business district.