The mother of missing RAF serviceman Corrie McKeague says she has passed on allegations to the police that her son was a victim of a crime.
Nicola Urquhart said she was concerned other lines of enquiry had not been followed up after the search focused on a landfill site in Milton, Cambridgeshire.
Speaking to Sky News, Mrs Urquhart said: 'We have had various calls suggesting a crime, but when we passed them on to police they took little action to follow them up.
'I spoke to the senior investigating officer two weeks ago and mentioned one call that we alerted them to, but she said she knew nothing about it.'
Mrs Urquhart said she had been reassured by police that other leads are now being followed up.
Corrie, who was based at RAF Honington, went missing after a night out with friends in Bury St Edmunds on September 24 2016.
He was last being seen on CCTV at 3.24am near a loading area behind Greggs known as the Horseshoe.
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A independent report by the East Midlands Special Operations Unit concluded Suffolk police had conducted 'a thorough, methodical and detailed investigation'.
Speaking after the second search came to a close last week, Detective Superintendent Katie Elliott said: 'We are still committed to continuing with the inquiry.
'There are a number of other theories about what could have happened to Corrie and we are continuing to test the evidence to help us understand what happened to Corrie, which will assist in providing answers to his family.'
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