After you beat the game you can access a passwords screen in the extra's menu, as well.
Input these passwords there.
Password --------
ItemAbraham --------- "Mobs Alive" (Ipod song)
George ---------- "Gekko" (Ipod song)
Theodore -------- "Midnight Shadow" (Ipod song)
Thomas --------- "Desperate Chase" (Ipod song)
dntkkhktmm ------ Drebin Face Camo
aottrykmyn ------ Altair Costume
mnsoymsyhn ----- Mosin Nagant
mekakorkkk ------ Mk. 23
deskyhstyl ------- D.E. (LB)
1aytmmymhk ---- 1911 Custom
jmsotsynrn ------ Type 17 Pistol
tshsniammr ------ Thor
pkhhnwhsjt ------ Patriot
skynytktjp ------- Scanning Plug S.
The two Ipod songs are the Policenauts Opening amd End Titles
And you have a bit of a spoiler in your post