Defense attorneys on Wednesday scrutinized the relationship between an admitted American terrorist and the Chicago businessman accused of helping him scout sites for the deadly 2008 Mumbai attacks, working to persuade jurors their client was merely manipulated by a trusted friend.

David Coleman Headley, an admitted drug user and high school dropout, has pleaded guilty for his role in the three-day siege by gunmen who killed more than 160 people. He agreed to testify against Tahawwur Rana, who is accused of providing cover as Headley conducted surveillance for the attacks, to avoid the death penalty.

Rana's attorneys wasted no time painting their client as a good guy with the wrong friend, setting up a main theme for the defense.

"He was your friend, but he didn't do what you were doing?" asked Rana defense attorney Charles Swift.

"Yes," Headley answered.

Headley, who was born in the U.S. but spent much of his life in Pakistan, is the government's top witness in a trial that comes at a fragile time in U.S.-Pakistan relations. His testimony has so far detailed how a Pakistani militant group blamed in the attacks and Pakistani intelligence coordinated in plotting and funding the attacks. The proceedings also come just weeks after Navy SEALs found Osama bin Laden hiding outside Islamabad, raising concerns that Pakistan may have been protecting the world's most wanted terrorist.

Rana and Headley, both 50, met years ago at a prestigious boarding school in Pakistan and have stayed in touch. But Headley detailed their different experiences under defense questioning.

Headley described Rana as a top student who attended medical school and adhered to strict religious beliefs, including no drinking alcohol or dating. Headley said he meanwhile used and smuggled drugs and dated multiple women.

When asked to describe himself as a student, he simply said, "Very bad."

Headley also told attorneys that he had tried to persuade Rana to join Lashkar-e-Taiba, the Pakistan-based terrorist group that claimed credit for the Mumbai attacks. But Rana declined because he said he didn't espouse the beliefs of group, generally made up of ultraconservative Salafi Muslims.

Headley, who said he started working with Lashkar in 2000, has testified that said the group and Pakistan's Inter-Services Intelligence agency, known as ISI, operate under the same umbrella. Pakistan has repeated what it's maintained since 2008: The ISI had no links to Lashkar.

Rana's attorneys on Wednesday questioned Headley's claims that he met regularly and received money from someone he said was an ISI major, known only as "Major Iqbal" and his Lashkar handler Sajid Mir.

"What's Major Iqbal's full name?" Swift asked.

"I don't know it," Headley answered.

Defense attorneys were expected to continue Headley's cross examination Thursday.

Earlier Wednesday as a witness for the prosecution, Headley testified that Rana praised the Mumbai attacks.

"'Tactically, this was done brilliantly'," Rana said, according to Headley's testimony.

Prosecutors also showed video surveillance that Headley took in Copenhagen for a potential attack in Denmark. Headley admitted to helping plan an attack that never happened on a Danish newspaper that in 2005 printed cartoons of the Prophet Muhammad.

Headley described for jurors Wednesday how he rode a bike around Copenhagen and conducted surveillance on sites including the French Embassy.

All developments were communicated with Rana, Mir and Iqbal, Headley testified.

Headley told Rana that he liked several other sites for future attacks, according to a transcript of a September 2009 phone conversation. The conversations, spoken in Urdu, were translated into English and read aloud for court.

Those sites included the Jyllands-Posten newspaper offices, Bollywood, the Somnath Temple in India and offices of Shiv Sena, a right-wing Indian political party.

Rana also praised the work of the gunmen and Mir, and said the nine of 10 who died should be given military honors in Pakistan, Headley testified.

Iqbal, Mir and Abdur Rehman Hashim Syed are identified by prosecutors as a retired Pakistani military with links to Iqbal. All three are charged in absentia.