Police have been scouring the area since the remains were found near Jaguar Land Rover's plant in Solihull on Wednesday.
In 2006 nearby land, just off Old Damson Lane near Birmingham International Airport, was searched by police looking for missing boys David Spencer and Patrick Warren.
At the time police suspected former Shropshire agricultural worker and convicted child killer Brian Field of having kidnapped the youngsters.
However so far there is no evidence linking the remains found this week to David and Patrick, according to West Midlands Police.
The boys were aged 11 and 13 respectively when they disappeared from their homes in Chelmsley Wood on Boxing Day 1996.
The boys, who became known as the 'Milk Carton Kids' after the publicity campaign to try and track them down, lived around three miles from where the remains were found this week.
On Friday morning, specialist police teams were at the site conducting a fingertip search and placing markers down while forensics officers and archaeologists examined the area.
A large blue tent was placed in front of an excavator and part of the diggers' caterpillar tracks have also been preserved with blue sheeting.
A spokesman for West Midlands Police said: "We are investigating after human remains were discovered on land off Damson Parkway, Solihull.
"The area has been cordoned off for further searches to be carried out.
"The bones will undergo forensic and archaeological analysis."
When asked if the discovery was connected to the missing schoolboys, the spokesman added: "There is no information linking them to a criminal investigation at this stage."
Land nearby was previously searched when police reopened the investigation to the boys' disappearance in 2006 and questioned paedophile and murderer Brian Field.
Field, an agricultural worker who killed Roy Tutill in 1968, had been living working as a gardener and odd-job man when the boys went missing.
At the time he was living freely, with police unaware he had murdered Roy until he was arrested for drink driving in 1999 and police took a swap of his DNA.
In 1996 Field lived in Rowood Drive, just metres away from where the remains have been found.
In 2001 he was jailed for life for the rape and murder of 14-year-old Roy.
Officers visited Field in prison in 2006 and questioned him about their disappearance but he denied any involvement.
The first search off Old Damson Lane was abandoned after several weeks with nothing having been found.
At the time, police said Field was just one line of enquiry. During their investigations police also arrested a 37-year-old man but released him after questioning.
Jaguar Land Rover has been approached for comment.
Who is Brian Field?
The former Shropshire farmworker escaped justice for 33 years but was finally jailed at the Old Bailey for the murder of Roy Tutill in 2001.
Field, now aged in his 80s, moved to Weston Rhyn, near Oswestry, just six weeks after strangling the schoolboy in a Surrey layby.
He had a string of sex convictions at courts in Shropshire and was also jailed in 1986 for kidnapping two boys.
In November 1972 he was jailed for two years at Aberdeen Sheriff's Court for indecently assaulting a 14-year-old boy who he pounced on along a country lane.
He worked as a milking engineer in north Shropshire in the 1980s and was twice jailed for offences in the county.
While living in Shropshire he was convicted and fined at Wrexham Magistrates Court or gross indecency, after he passed obscene notes to undercover police in a public lavatory.
In April 1982 he was fined for gross indecency at Oswestry Magistrates Court after fondling a 17-year-old boy, then in September 1983 at Shrewsbury Crown Court, Field was jailed for four years after being convicted for two serious sexual offences.
At Stafford Crown Court in June 1986 Field was jailed for four years for falsely imprisoning two teenagers. The boys aged 13 and 16, had been walking between Weston Rhyn and St Martins, near Oswestry, when they were given a lift by Field.
He threatened them with a wheel brace and then forced them to remove their clothing.
The terrified boys escaped by jumping from the moving car.
After his release, Field went to live in Solihull where he worked as a farm labourer. Unknown to police he was harbouring a dreadful secret - the murder of Roy Tuthill in Surrey in 1968 as the schoolboy walked home from school. Soon after the murder he moved to Shropshire.
His crime stayed undiscovered until he was arrested for drink driving in 1999 in the Midlands.
A mouth swab showed samples of DNA that matched a sample taken from the scene of the murder. At first he vehemently denied his involvement, until police told him about the match.
In 2001 he was jailed for life for the murder. Police feared that he could have been responsible for murdering dozens of young boys, including David Spencer and Patrick Warren who they quizzed Field about in 2006.