The ex-pat, who still lives in Portugal’s Algarve, was working near the apartment where she vanished on May 3, 2007.
This week he has been quizzed by police over his whereabouts between the critical hours of 7pm to 9.30pm, the Sunday People can reveal.
That evening Madeleine’s parents Gerry, 45, and Kate, 46, went for a meal with friends at the Ocean Club resort, Praia da Luz, where they were staying.
They left Madeleine, then three, and their two-year-old twins in their holiday flat about 80 yards away.
The self-employed gardener and handyman was seen by British and Portuguese officers at a police station in Faro on Wednesday.
The gardener, who has lived in Portugal for more than a decade, has strongly denied any involvement in Madeleine’s disappearance.
According to the official timeline of that night, dad Gerry left the meal to check on the children at apartment 5A at 9.15pm.
Kate raised the alarm at 10pm when she realised Madeleine had gone.
The gardener, who lived with a companion in Praia da Luz until 2006, gave a mouth swab to Portuguese police when he gave his statement in 2007.
In his original interview he denied seeing anything strange at the time of Madeleine’s abduction or having ever seen the family before the abduction.
He has now been identified as one of seven new possible suspects – five men and two women – who detectives believe could hold vital information.
A British woman is also believed to have been questioned this week by officers from Operation Grange, the fresh Madeleine inquiry ordered by David Cameron three years ago.
Four others are men from Portugal and the seventh is understood to be a woman of Central or Eastern European origin.
All of them were ordered to provide fresh DNA samples which will be matched against samples of evidence taken from the resort in Praia da Luz.
Insiders said they will be classed as persons of interest – known as “arguidos” in Portuguese law.
It is understood some of the possible suspects know each other or worked together at the Ocean Club resort.
At least two are believed to have criminal records and some exchanged phone calls on the night Madeleine vanished.
A source said: “Officers from Operation Grange have reviewed several statements given at the time Madeleine went missing and have identified several points they believe still need answering.
"They will interview, re-interview and then review several people and their statements and then refocus again at the end of the month.”
A Metropolitan Police spokesman said the force would not officially comment on the continuing investigation.
The developments come two weeks after it emerged that forensic experts were unable to find a DNA match for 98 hair strands found during the original police probe.
Scotland Yard experts believes these hairs could hold the key to solving the case.