Brisbane drain soil yields no clues relating to cold-case murder of Sharron Phillips

Detectives trying to solve the cold-case murder of Sharron Phillips have failed to find any trace of the missing woman after sieving through piles of soil taken from two Brisbane drains.

Officers cleared out the drains in recent weeks after receiving credible information that the 20-year-old's body may have been dumped on council-owned land at Carole Park.

The soil however failed to give up anything related to the investigation.

Police say they remain committed to solving the crime, and the family of Ms Phillips has been informed.

Ms Phillips vanished from Wacol on the night of May 8, 1986, after her car ran out of petrol.

Investigators are looking at the possibility she was picked up by a taxi driver, who is connected to a witness who has come forward with new information in recent weeks.

It was the witness's information that led police to search the Carole Park site, which is not far from where Ms Phillips was last seen waiting for her boyfriend after using a public phone.

Investigators have also received more than 30 new leads through Crime Stoppers after recent media coverage about the unsolved crime.

The case took an unexpected twist in May of this year when Ms Phillips' siblings questioned the alibi of their father Bob, who died in 2015.

With AAP.