Anthony Joseph Zimmerman

Anthony Joseph Zimmerman, a Cingular network engineer, testified by telephone on Day 18 of Steven Avery's trial about Teresa Halbach's cellphone and voicemail records. He said the records showed no cellphone activity after about 2:41 p.m. on October 31, 2005, but that the records alone could not explain why the account became inactive.

On direct examination, Zimmerman explained that a voicemail's “received” timestamp recorded when it entered the mailbox, not when someone retrieved it. He described eight unopened messages and ten old, saved messages. In his opinion, a saved message had been heard at least partly and most likely in full, but he could not determine when. He also explained that someone with the password could access the mailbox from another phone; he did not say that anyone had done so.

On cross-examination, Zimmerman clarified that a message could be marked as listened to without being saved, even if the listener skipped it after playback began. He said the report could not show when messages were heard or saved, or establish whether or when other messages had been erased. He thought the listed messages would not have filled the mailbox. If a caller heard a mailbox-full recording on November 3, he said, at least one message would have had to be removed before a later message shown on the report arrived. That conditional answer did not identify who, if anyone, removed a message. After his testimony, counsel confirmed that the defense had agreed to the telephone procedure and had no objection to its use for Zimmerman.