Final answer:
The actual phone number Detective Morrison decided to use is not provided in the question. The details focus on decision-making in investigations and illustrate the importance of careful handling of witness testimony, as demonstrated by the cases mentioned.
Step-by-step explanation:
The question doesn’t provide enough information to definitively answer what phone number Detective Morrison finally decided to use for the "Matt is missing" posters. Instead, it seems to be a general inquiry about decision-making in a police investigation, particularly regarding witness reliability and police interaction. However, based on common practice, a detective may opt to use a personal number if they believe it would lead to more credible and controlled tips in an ongoing investigation. In both provided scenarios, detectives are dealing with sensitive cases, yet only the second scenario provides specifics about the case details, referencing Detective Mark Holste investigating a report from a neighbor and not associated with creating posters or phone numbers.
In the case of Jennifer Thompson and Ronald Cotton, the focus is on the issues surrounding eyewitness identification and the potential for misidentification due to suggestive actions by law enforcement. This highlights the importance of careful and unbiased handling of witness testimony in criminal investigations to prevent wrongful convictions, like what happened to Ronald Cotton.