A court has heard evidence indicating the signal of real estate agent Yanfei Bao's phone was picked up at the same locations around the city as her alleged killer on the day she disappeared.

Tingjun Cao is on trial for the murder of the 44-year-old mum, a charge he denies.

The defendant wasn’t in the courtroom at the Christchurch High Court today, with a Mandarin translation of proceedings instead provided to him remotely through a headset.

The day after Yanfei Bao disappeared in July last year, her phone was found discarded alongside Christchurch’s Southern Motorway.

Detective Michael Hawke told the court where he found it.

“I located Ms Bao’s cell phone in a bush. It appeared to have been snapped in half. I called Ms Bao’s number ... the call connected; however, the phone was not ringing."

Detective Joel Syme said: "Data indicated that prior to it being found by police, Ms Bao's cell phone had been polling at Halswell Village and Tai Tapu cell towers.

"Cao's vehicle had been seen on traffic cameras in the same or similar areas at the time Cao's cell phone was polling in those areas."

Police sought a special warrant to keep an eye on the defendant.

Detective Syme said this was done, "to intercept the communication of Cao through any mobile cellular device believed to be being used by or in position or under the control of Cao... and to track the general location and movements of Cao."

Cao's car was also forensically analysed, Detective Kim Hendrie told the court.

“ESR located a blood-like substance on the upper side of the inside of the boot of the vehicle. An initial test returned a positive result for blood."

The Crown contends that Tingjun Cao stowed Yanfei Bao's body in his boot before burying her on the outskirts of Christchurch.

The trial is continuing.