GUATEMALA CITY (AP) — Ex-Vice President Roxana Baldetti was detained Friday in connection with a customs corruption scandal that led to her resignation, and prosecutors announced they are seeking to investigate President Otto Perez Molina in the matter.

Prosecutors said they have enough evidence to presume that Baldetti, who is suspected of illicit association, fraud and graft, took part in a scheme that is believed to have defrauded the state of millions of dollars.

They said they are seeking to have Perez Molina's immunity of office withdrawn so they can investigate his possible involvement.

Documents seized in raids "lead one to consider it highly probable that the president of the republic may have participated in the same" scheme, Attorney General Thelma Aldana said at a news conference.

Perez Molina said he did not know what was in the prosecutor's complaint, but would find out and then comment.

"We are going to face it head on, we are going to keep facing it," he said at a public event in Zacapa department 150 kilometers (90 miles) east of Guatemala City.

He has repeatedly denied involvement, and a recent bid to lift his immunity died in Congress last week.

Baldetti was informed of her detention at a hospital where she was seeking treatment for health problems. She has denied any involvement in the scandal at the customs agency, which involved kickbacks paid by businesspeople to avoid import duties.

A judge ordered a medical examination of Baldetti to establish her health. The National Forensic Sciences Institute said Baldetti was healthy and could face justice.

A criminal ring known as "La Linea," or "The Line," was allegedly led by Baldetti's aide, Juan Carlos Monzon Rojas, who is currently a fugitive. Authorities presented a chart diagramming the structure's alleged organization that showed Monzon as the mastermind.

Baldetti resigned May 8 after an investigation spearheaded by prosecutors and a U.N. commission probing criminal networks in Guatemala led to arrests of government officials and private citizens.

The U.N. commission has presented wiretap conversations related to the investigation in which participants mention "the R," ''the No. 2" and "the lady," suspected references to the vice president.

Commission chief Ivan Velasquez said investigators suspect that in just one week, bribes could have totaled at least $262,000.

"This has been a very complex investigation that still requires a lot of analysis, and we are continuing to collect evidence," Velasquez said.

Guatemala has seen large protests over the scandal and another multimillion-dollar corruption scheme that rocked the nation's social security institute.

Presidential elections have been scheduled for September. Guatemalan presidents are limited to a single four-year term, so Perez Molina is ineligible to run for re-election.

Friday afternoon, hundreds of people celebrated in front of the national palace and called for the resignation of Perez Molina.