UK Anti-Doping chief executive Nicole Sapstead has launched a scathing attack on British Cycling, Team Sky and their doctor Richard Freeman for failing to keep proper records of drugs given to riders in their care.

Appearing before the House of Commons’ Culture, Media and Sport select committee, Sapstead told MPs her agency has been investigating allegations of wrongdoing in British cycling since September, when it received information about a package delivered to Freeman for star rider Bradley Wiggins at the end of the Criterium du Dauphine race in June 2011.

She told the panel UKAD has interviewed 34 current and former riders and staff members at British Cycling and Team Sky, in an investigation that has taken up more 1,000 man-hours, often at the detriment of other work.

But, in a shocking revelation, she said UKAD still does not know if the legal decongestant Fluimucil was in the package, as Freeman says, as opposed to the allegation in the original tip-off that it contained the banned corticosteroid triamcinolone, because there is no paperwork.

She said: "We are not able to confirm or refute that it contained Fluimucil. We have asked for inventories and medical records and we have not been able to ascertain that because there are no records."

When asked by the panel why Freeman cannot produce any evidence that he gave what was an unlicensed product in the UK to Wiggins, as he is obliged to do under correct medical practice, Sapstead said: "There are no records... he kept medical records on a laptop and he was meant, according to Team Sky policy, to upload those records to a dropbox that the other team doctors had access to.

"But he didn't do that, for whatever reason, and in 2014 his laptop was stolen while he was on holiday in Greece."

Sapstead said UKAD has contacted Interpol to check if this theft was reported at the time but has not received any confirmation it was, although Freeman did report it to British Cycling at the time.

Freeman pulled out of his scheduled hearing because he was "too unwell" to attend.