You decide to do some sleuthing, you watch him during the day, nothing suspicious, he keeps to himself mostly, he goes to work, he runs his errands then he goes home.
Saturdays and Sundays he devotes to his hobbies, swimming, boating, etc, he is 36.
You look up his finances, nothing odd, pays taxes and bills and shopping, his ocean side house is paid off.
You do notice however that every month 5% is withdrawn in cash and not accounted for.
One night you get him to work late at the office so you search his house, it is a detached house, nice garden, ocean side and he keeps a boat there.
You search the boat, fairly normal, small cabin, well cared for engine, most likely he likes speeding it around and going swimming in the summer.
You search the cupboards, nothing abnormal, a few typical boating supplies, some overnight gear for long trips, very clean, most suspicious thing is a bottle of thick bleach and a bag of sponges.
You search his car and find nothing.
You decide then to search his house, it is fairly minimal, hardwood floors, white washed walls and ceiling, minimal furnishings.
The living room is typical, a chair and a sofa aimed towards the television, a side table with a lamp and iPad on it (for Netlix etc)
The bathroom is also not suspicious, you search his kitchen, the same, except under the sink is full of bin bags and bleach.
The spare bedroom has been converted into a gym, you find that he is incredibly fit and a black belt in many martial arts.
Added (1). Then you hit the possible mother load
You look in his office and initially don't find much, then you search his computer and notice that he has police software and he has researched a number of violent criminals who were released but have been reported missing.
After looking in an air-conditioning vent he has a file on each of the missing criminals saved, all with a red X painted on them.
You search his bedroom, you find he keeps a loaded handgun under his mattress and then later find another on
Added (2). another one concealed inside his living room sofa.
You also look in a crawlspace under his wardrobe and find a duffel bag, containing $100,000 cash, passports and drivers licenses of different countries US passports, they all have his picture in with different names.
You also find in the bag, a wash kit and a change of clothes, list of escape plans and a blade.
In the same crawlspace you find a briefcase, containing newspaper articles and details of his past, that he has clearly saved.
Added (3). Before you leave you look in a chest in his shed and find a duffel bag of tools including a power saw, a hatchet, various knives and loads of masking tape and plastic sheets.
When you go home you do some research on what you found to be his original identity, and find that he is wanted in Missouri.
From archived newspaper articles you find that he was the only son to a single mother, who was violently murdered by a group of teenagers when he was 8.
he went into care and when he turned 13.
Added (4). he found and murdered most of the group violently, he was found guilty and institutionalized, at 17 he escaped the asylum, murdered the surviving members of the group before disappearing again.
Read more: What would you do if you were investigating someone and found this?