This is a public service graffiti
What do you think of this?

"First Graham Bell astonished the world with the telephone, then he spooked the criminals". It isn't very clear, but above this main text there is a telephone number in red with the text "Disque Denúncia" - it's a police number so you can report criminals.
I spotted it a little while back near Jardim Botanico and it sent me running for my dictionary. Assombrou is the third-person past-tense of Assombrar – which can mean haunt, amaze, astonish, stupefy, petrify and a bunch of other translations. When I asked a colleague they suggested that in this context you might use ‘freak out’, i.e. he astonished the world and then freaked out the criminals.
Anyway, however you translate it, it’s an unusual piece of graffiti isn’t it? So often graffiti seems to be anti-establishment and here is something encouraging people to inform on criminals!
It struck me as so unusual that I did a little digging and found that this is actually part of a series carried out by an advertising agency, presumably on behalf of the mayor, city, police. Here are the other two (courtesy of http://buzzpubli.blogspot.com/):

"It's a phone delivery: You call and the criminals get the police on their doorstep". Your handcuffs sir, sorry we took so long...

"Crimes are like puzzles. When you have more *connections*, it is easier to find a solution" - bit of a tricky one this - "ligação" can mean phone call or it can mean link or connection.
Looking at that last one, I just have to say quickly how much I like the Portuguese word for puzzle, quebra-cabeça – head-breaker!

Could these actually be from the public safety department? They are interesting.
And if they aren’t done by some municipal people, then we have a good Samaritan graffiti artist plaguing Rio.
I liked the idea of it being done by some secret (possibly masked, possibly wearing tights) vigilante who roamed the night spraying this and other messages of responsibility to the public. “Don’t use your cellphone while driving”, “Help old ladies across the road”, that kind of thing.
But yeah, turns out it was done by an advertising agency and presumably commissioned by the mayor’s office or some other official body…
How about using “spooked” for the second “Assombrou” in that first piece? Just to keep it ghost friendly :-)
Yeah, “spooked” would be just about perfect, good one.