The sensational trial, in which Arias, 32, is accused of stabbing Alexander multiple times, slitting his throat and shooting him in the head, centered Monday on prosecution attorney Juan Martinez's accusation Arias had lied to law enforcement authorities and attempted to deflect suspicion by sending flowers to Alexander's family after she killed him.
Martinez claimed Arias planned an alibi after she killed him, and days later phoned friends and family to learn "if anyone was onto you."
Arias responded by saying she remembered little of the killing, azcentral.com reported.
Testimony in the trial is in its eighth week.
The trial, which has involved kinky sex, confessed lies, nude photos and the admission by Arias she killed Alexander, includes a claim by the prosecution Arias sent coded messages, hidden in copies of the Star and Digital Photo Pro magazines, to a friend, Ann Campbell, while Arias was incarcerated in 2011, ABC News said.
Martinez told jurors Thursday he suspected the messages are evidence of Arias' attempt to manipulate the testimony of a witness.
Strung together, numbers written in pencil in the magazines' margins could be interpreted to read "Get down here and see me ... before you testify so we can fix this," Martinez told the jury Thursday.