Two or three teens going around Mid-Cambridge robbing people on the street, police say

Cambridge Police report they are investigating a string of street robberies this week in which people have been held up, at least once at knifepoint, in Mid-Cambridge north of Massachusetts Avenue:

Around 6:10 p.m. on Tuesday at Inman and West streets, a man was approached by two black teens, about 16, 5'10" or 6' tall in dark hoodies, who first asked him for change, then when he refused demanded all his money, with one pointing to his waist as if he had a weapon.

Around 1:20 a.m. on Wednesday, on Bishop Allen Drive near Essex Street, a food-delivery man was approached by two black teens in black clothing after he got out of his car to delivery food. One motioned to his waist; the two then stole both the food and $50 in cash.

Around 9 p.m. on Thursday, also on Bishop Allen Drive near Essex Street, another food-delivery man was robbed at knifepoint, this time by three young black men in hoodies, who took the food and $20 in cash.

Around 11:42 p.m. on Thursday, a man walking on Harvard Street near Clinton Street was approached by two black teens in dark hoodies, who asked him for change for a $10 bill. When he gave them two $5s, the suspects put their hands on his shoulders and demanded his wallet. He yelled at them and they fled.

Police have increased nighttime patrols in the area and ask anybody with information to call them at 617-349-3300.