CORFU (AP) - Authorities are investigating whether robberies committed at four Western New York branches of the same bank are related.

Two of the robberies occurred within minutes of each other the afternoon of Jan. 3 in Amherst and in the Genesee County village of Corfu, 25 miles east of Buffalo.

In each robbery, police say a man walked into an M&T Bank branch, demanded money from a teller and left with an undetermined amount of cash.

Police believe the man who robbed the Amherst bank also robbed the same branch Dec. 17.

Two M&T branches in Buffalo were robbed about 15 minutes apart last Friday.

No arrests have been reported.