Who else can help me solve this case?

Hint 1 of 20:

Note: in the interest of saving space, I've left out phrases like "Go to that
location."  If I mention a place/person in any way, you should visit it.

Hint 2 of 20:

You might want to start out by visiting the five victims' homes to see what
you can find out about them.

Hint 3 of 20:

Remember that Leo Shepard was not a victim -- Porky told you his real name.

Hint 4 of 20:

See Curtis Twiggs, Nathan Revell, Cyril Maude, Charles Attard, and Roland
Jaquard.