The Justice Department has declined to pursue charges against former Vice President Mike Pence in connection with his retention of classified documents at his home in Indiana, informing him in a brief letter on Thursday night, according to three people familiar with the situation.

Word that the case would be closed came days before Mr. Pence was set to announce his campaign for the Republican presidential nomination in Iowa.

The F.B.I. and the Justice Department’s national security division conducted an investigation into the potential mishandling of classified information, the department wrote to Mr. Pence’s lawyer, according to a person who had read the letter. Based on the results of that investigation, “no criminal charges will be sought,” according to that person.

In January, a lawyer for Mr. Pence searched the former vice president’s house for documents after aides to President Biden discovered a trove of sensitive material at an office he had once occupied in Delaware.

In contrast to former President Donald J. Trump, who defied a federal subpoena to return materials stored at his Florida residence, Mr. Pence quickly informed the government and said he was unaware how the material ended up at his house.

A special counsel is still investigating the retention of materials by Mr. Biden, who also cooperated with investigators.