Detectives believe they were targeting the family until the alarm was raised about Madeleine’s disappearance.
They discovered a series of eight calls and texts suggesting they were monitoring her parents, Kate and Gerry, before a raid on their apartment in Praia da Luz, Portugal, in May 2007.
Detectives try to find out if they intended to commit a heist or if they had a more sinister motive to keep an eye on the McCanns.
The first call was made by Suspect A, a 51-year-old heroin addict, to Suspect B, a then-only 16-year-old beggar, at 12:08 p.m. the day before Madeleine disappeared.
B then exchanged four phone calls and texts with suspect C, a 33-year-old former Ocean Club driver convicted of theft, on May 3.
The first was at 5:26 p.m., at the precise time when Madeleine left the crèche at the station.
A text was exchanged at 9:25 p.m. when two of the McCanns’ vacation buddies left their dinner at a tapas bar to check on the children in the group who were sleeping in neighboring apartments.
The two suspects were in touch again at 9:38 p.m. when one of the McCanns’ friends, Jane Tanner, left the restaurant to check on her children.
They resumed contact at 9:51 p.m. as the mother of Madeleine’s general practitioner was on her way to her apartment to find her then three-year-old daughter missing.
Later that evening, A made three calls from a public phone booth in the resort to B.
Police still have not located a man seen carrying a sleeping blonde girl in pajamas towards the resort beach at 10 p.m.
Yesterday, Scotland Yard officers, including Detective Chief Inspector Andy Redwood, joined Portuguese detectives to continue investigating the three men bound by the calls.
Sources said suspicious hair was also found that did not match Madeleine’s DNA. According to Portuguese newspapers, a request to obtain DNA and fingerprints from the three men was refused.
They deny any involvement in Madeleine’s disappearance and answered more than 250 questions from the police. Yesterday UK police sniffer dogs were brought in to examine the cars of suspects A and C.
According to a Portuguese newspaper, thefts had tripled at the Ocean Club at the time of Madeleine’s disappearance.
None of the men commented as they left a police station in Faro.
A friend of suspect A, who a private investigator hired by the McCanns said he “would do anything for his next solution,” insisted he was innocent.
“He was inside the night Madeleine disappeared,” his friend said.
“It is inhuman that a patient like him is dragged in front of the police.
A fourth suspect, a Russian, was also questioned. Yesterday, police questioned eight people as witnesses.