Federal prosecutors say a presidential historian charged in a plot to steal historical documents from archives in several states has tried to influence others in the case and hinder the investigation from jail.

Prosecutor James Warwick argued Thursday against the release of Barry Landau, saying he poses a flight risk and may try to obstruct justice if he is released.

Landau and an assistant are charged with conspiring to take documents from the Maryland Historical Society and other archives.

Warwick says Landau has tried to get another person to take the blame, offering to pay for a psychiatric defense. He also says items left in Landau's New York apartment after a July search disappeared before a second search on Tuesday.

Prosecutors plan to appeal if he is released.