A juvenile has been arrested in a string of robberies in the Capitol Hill neighborhood — including three that occurred in a four-hour time span last week, according to D.C. police.

The first attack occurred Jan. 14 in the 700 block of 8th Street SE, two blocks south of the Eastern Market Metro. Police said the victim was getting into his parked car about 8 p.m. when a youth approached him and demanded property. Police said the youth implied that he was armed.

Authorities also allege that the youth — whose name was withheld because he is charged as a juvenile — struck three times on Jan. 23, starting at about 4:30 p.m. when he approached a man walking home at 11th and E streets NE.

Police said the youth threatened the victim from behind with a knife, and took money and a cell phone.

About 90 minutes later and three blocks away, in the 800 block of Maryland Avenue NE, police said another man walking home was robbed of his money. In this case, police say, the youth implied he had a weapon.

At 8 p.m,. in the 300 block of A Street SE, police say a youth ran up behind a man and snatched a cell phone from his hand.

Authorities did not release information about the suspect’s exact age or where he lives, or the circumstances of his arrest.

Capitol Hill has been a frequent target for robbers. In December, 28-year-old Jason Emma was shot and killed as he returned to his Capitol Hill home on C Street Northeast. Police said they are investigating the slaying as a robbery.

In August, Thomas C. Maslin was severely beaten and left unconscious and robbed while walking home from an evening out at Eastern Market. Police have arrested several suspects in the attack.