The subject's past employers and business associates, his landlords and landladies, his friends and enemies, and his milkman must be run down and interrogated.

Perhaps his personal movements must be watched.

Any intelligent fellow who is out of a job will do this for you for about $5 a day and expenses.

The agencies usually charge from $6 to $8 (and up), and prefer two men to one, as a matter of convenience and to make sure that the subject is fully covered.

If the suspect is on the move and trains or steamships must be met, you have practically no choice but to employ a national agency.