Officers began scouring scrubland yesterday with X-ray ground scanners and dogs trained to sniff out dead bodies in a search to find Nicola Payne.
Miss Payne was just 18 when she went missing in Courthouse Green, Coventry, West Mids, on December 14, 1991.
Two men, aged 74 and 45, from Coventry, were arrested today on suspicion of conspiracy to prevent the lawful and decent burial of a body.
Detectives said the arrests followed new information which has come to light in connection with the inquiry.
West Midlands Police said they are being held at police stations in the city where they will be questioned by detectives in connection with Nicola's disappearance nearly 21 years ago.
Meanwhile, officers continue to carry out a detailed search of an area of parkland off Purcell Road in Coventry, after initial searches by police and scientists revealed areas of interest.
These areas will now be further examined using specialist equipment including metal detecting devices and other specialist equipment.
The site where police are digging is just a few hundred metres away from where she was last seen 21 years ago, close to the home she shared with her parents and her seven-month old son Owen.
Since her disappearance her family have campaigned tirelessly to find out what happened.
Speaking in 2007, her son Owen who is now 21, described how he had missed out on memories with his mum.
He said: "I was seven months old when my lovely mum Nickie went missing. Nan and granddad always say that she had a loving bond with me, which was noticeable to all.
"Sadly I have no memories of her and I envy my older cousins who remember her well, and they tell me what a fun loving girl she was.
"During my early years at school I wished that my mum could meet me at the school gates after school to collect me, as other mums did with my friends.
"School plays, sports days and open days - there was no mum there to spoil me. My dad and all the family were always loving and caring, but it wasn't the same.
"I am now 16 years old and have just left school and hoping to become an electrician.
"My one wish would be to have my mum found and to be able to understand the confusion, mystery and heartbreak of the past 16 years.
"Please support me and help in anyway you can. There are people out there who know what has happened to her and would make my nan and granddad so much happier."
When Nicola disappeared, she was 5ft 3in tall, of medium build, with brown hair and brown eyes.
She was last seen wearing a brown leather jacket, purple T-shirt and fawn trousers.
Nicola's family gave a statement following the latest search investigation to find Nicola.
They said: "It has been nearly 21 years since our daughter Nicola went missing. For many years we have suffered not knowing what has happened to her.
"This demonstrates that there are people still providing vital and important information to the price around her disappearance.
"If there is anyone who has information that will assist the police around this new site or witnessed anything around this location back in December 1991 please make contact with the officers.
"We are appealing as a family to find Nicola and to give us the clue we deserve."