Police investigating the death of Auckland mother Carmen Thomas will tomorrow concentrate on Whitford, a rural area 30km southeast of central Auckland.

Inquiry head Detective Inspector Mark Benefield confirmed at the weekend that police were looking for a killer after blood was found in the Auckland escort's car, which was abandoned on a Hamilton street.

As well, a wheelie bin was missing from her house.

Ms Thomas was reported missing on July 13 when she failed to collect her five-year-old son, Jack, who had been staying with friends.

There have been no confirmed sightings of her since June 27, her bank accounts had not been touched, and she had not contacted family or friends.

Mr Benefield tonight said staff would be in Sandstone Road, Whitford from about 6.30 am tomorrow following up on a reported sighting of her car parked in the area about the time she went missing.

"Uniformed staff and CIB (Criminal Investigation Branch) investigators will be on the road to try to speak with motorists who regularly travel along it to find out whether any of them recall seeing Carmen's car - a dark Nissan Pulsar three-door hatchback with the registration number ATS 209 - parked in the vicinity late in June or in the first week of July," he said.

"It's important we follow up on the information we've received and try to corroborate it or eliminate it as valid to our investigation as best we can and as soon as we can."

The serial number on the missing Auckland City Council blue-lidded 240 litre bin is 014 172.

"We don't know when it went missing and we won't know until we find it whether it's of significance to our investigation, but we'd very much like to locate it so that we can make our own determinations as to its importance or otherwise," he said at the weekend.

"Staff are firmly committed to finding her and bringing whoever is responsible for her death and disposal to account."