While Mr. Uribe has been accused of many crimes related to Colombia’s long civil conflict, which left more than 220,000 people dead, none until now were known to lead to his resignation from any office.

But recent cases have put more pressure on the former president and his circle. In addition to investigations of Mr. Uribe and his associates, Mr. Uribe’s brother Santiago is also expected to face trial related to allegations that he ran a death squad on his ranch called the Twelve Apostles.

On Tuesday, the Supreme Court said that it would investigate Álvaro Uribe and Álvaro Prada, another senator from his party, for “the crimes of bribery and procedural fraud” that, according to the accusation, took place this year and were related to witness tampering.

The case stems from an earlier attempt by Iván Cepeda, a left-wing senator who has often sparred with Mr. Uribe, to investigate allegations that Mr. Uribe founded a death squad in his home province, Antioquia, before he became president.

Mr. Cepeda published a book on the subject. Mr. Uribe claimed that witnesses received money for their interviews, and he accused Mr. Cepeda of witness tampering.

In February, the Supreme Court dismissed the case against Mr. Cepeda and said it was opening an investigation into Mr. Uribe for witness tampering. The tables were now turned against the former president.

Some witnesses in the cases against Mr. Uribe and his associates have been killed in recent years in crimes that remain unsolved.