Few investigators are aware of what a mail cover is, what is required to obtain one, or what the potential benefits are. In general, a mail cover is a process by which a nonconsensual record is made of any data appearing on the outside of any mail being delivered to a particular address. This includes the addressee, sender, return address, place and date of postmark and class of mail. Since the mail is not opened, this investigative method is not prohibited under the Fourth Amendment.
Investigators can make arrangements for a mail cover with the US Postal Inspector in your jurisdiction, provided the punishment for the crime you are investigating exceeds one year in prison and you can articulate what information you are hoping to find and how it will assist your investigation. Mail covers are limited to 30 days unless adequate justification is provided for extending it.
Mail covers can be beneficial in obtaining evidence of the commission of a crime, identification of associates, locating fugitives (i.e., writing home to a girlfriend or relative), and the identification of property, proceeds and assets that are forfeitable (i.e., which banks the suspect has accounts).
No investigator is able to obtain a confession all of the time. Therefore, when relying solely on a confession to make a case, you must approach the situation laterally instead of head-on. The one weakness that most every suspect has is his loose lips or bragging about the incident to others. Find the person the suspect is willing to talk to and exploit this weakness to your advantage by recording the conversation, if possible.
In many cases, the suspect will have discussed his involvement in the crime with someone close to him. These people are far more likely to speak to you and make statements that incriminate your suspect than the direct questioning of the suspect himself. Talk to the suspect's friends, relatives, and acquaintances to learn about the suspect and his involvement in the crime. Then, use the information you obtained as leverage against the suspect when finally confronting him.
The motivation of others to assist you varies from case to case. In some instances, an informant may approach you out of civic duty or simply because it's the right thing to do. Others may desire payment, and, in some circumstances, you can use a criminal informant for assistance.
Criminal informants generally provide information or act in an undercover capacity in exchange for prosecutorial consideration on a charge they themselves are facing. Because of their criminal background and desire to help themselves, you must exercise great care when utilizing these types of informants to avoid obtaining false information.
If you are having difficulty getting an associate to speak to you, reassure him that he is actually helping his friend, not ratting on him. Be prepared to act on the information immediately, as the person may later rethink his desire to assist you.
If you are having trouble identifying a person with potential knowledge of the crime, try utilizing the media by offering a reward for information. If your department is strapped for cash, organizations such as CrimeStoppers will often assist by putting up the reward money. If a suspect has not yet been developed, consider using a forensic artist to develop a composite drawing of the suspect, using the media to publicize.
Patrol officers often have local sources of information and can also ask each citizen they come into contact with every day, such as on a traffic stop, if they have any information that may be useful. Encourage the relay of any and all information, even that which they may feel is insignificant, common knowledge, or rumor (but identify rumors as such).
In situations where you have one person's word against another, a recorded phone call to the suspect from the victim can yield the break in the case you need. …