Portland police are investigating a string of four robberies in three days that included the TD Bank in the Westgate Shopping Center on Congress Street, a police spokesman said.

The first, on Saturday, occurred at 9:45 p.m. at the CVS at 449 Forest Ave.

Two robberies were reported Sunday, the first at about 5:50 p.m. at the Walgreens on Marginal Way. The second was reported at about 8:30 p.m. at the Domino’s pizza on Forest Avenue.

The fourth robbery happened around 9:30 a.m. Monday at the TD Bank.

“They may be connected. It might be the same person,” said police spokesman David Singer said. No one has been arrested.

Singer declined to say why he believed the robberies were connected. He also declined to answer questions about whether the perpetrators were armed or threatened store employees.

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