Update: Lincolnshire Police confirmed a third man has now been arrested in connection with the incident.
A 28-year-old was detained on the evening of Wednesday, June 6 on suspicion of robbery and remains in custody for questioning.
Two men were arrested over the weekend in relation to a robbery at a Co-op store in Ancaster.
As previously reported, men reportedly entered the store on Ermine Street just after 10.30pm on Wednesday, May 30 and demanded money from a member of staff in the supermarket.
Police said the men made off with a quantity of cash, but nobody was injured during the incident.
Jack Hess, 25, and Josh McLellan, 22, both from Peterborough, were charged with conspiracy to commit robbery and will appear in custody at Lincoln Magistrates Court on Monday, June 4.
McLellan was also charged with driving whilst disqualified.
Police said: “The detectives on the case have also renewed their appeal for witnesses and any further information about the robbery which was reported to us just after 10.30 on Wednesday evening May 30 at the Co-op Food Store, Ermine Street, Ancaster.
“Anyone who thinks they can help should call 101 and quote incident number 452 of 30th May. All contact will be treated in the strictest of confidence.”