PORTLAND, Ore. -- A man accused of three convenience store robberies was caught on camera.

Portland police said the man used a knife during a robbery at a Plaid Pantry on Oct. 29 on Hayden Island Drive. Earlier that night, he approached the clerk at the counter of a Plaid Pantry on North Greeley Avenue and verbally demanded money, police said.

On Nov. 5, he returned to the Greeley Avenue store at about 7:30 p.m., according to police. He grabbed the clerk by her sweater and demanded money from the cash register.

In all three robberies, he escaped with an undisclosed amount of cash.

The robber is described as a black man in his mid-30s between 5 feet 7 inches and 6 feet tall, about 175 pounds and bald. In the first two robberies, he wore a dark blue hooded sweatshirt with the words "Polo Jeans" on the front, faded jeans and black and white athletic shoes.

In the third robbery, he wore a black jacket with a white shirt and gray sweatpants.

A $1,000 reward is being offered for information that leads to the arrest of the man. Anyone with information is asked to call 503-823-4357.

Police Seek Man In 3 Plaid Pantry Robberies

Raw Surveillance Video: Plaid Pantry Robberies