Before signing the lease, I specifically asked whether there were any bed bugs ever present in the apartment or any other units in the building, and the building manager swore that there were none in this building. After discovering the bed bugs, I immediately called my building manager the next morning to have him hire an exterminator to rectify the issue. After a series of phone calls, during which the building manager tried to blame the problem on me and convince me to contribute to the extermination costs, and then threatening to do nothing and yelled at me when I told him I knew he was legally obliged to handle the situation he finally called an exterminator. During one of those phone calls, he admitted that a few of the other buildings they managed ha bed bugs.
The exterminator called me the next day (Friday) to schedule an appointment for the following Monday- he did nothing to inform me of how to prepare my apartment, yet luckily I researched online and had my apartment totally prepared for treatment. 
After being 2 hours late, the guy finally came and spent just under an hour treating my apartment, claiming it was a very isolated issue- yet he did not even check or treat everything as he should have. And when I asked him to treat the holes and cracks in the walls, he said it was unnecessary. Immediately after the treatment, I sealed up my mattress and box spring with expensive covers to protect against bed bugs and kept all my clothes, linens, and son's plush toys in sealed plastic bags. A week later he returned for a second treatment, was 3 hours late this time, and spent no more than 10 minutes spraying my apartment. I even told him that I knew they were in the walls as I mostly saw them out visible cracks and holes. He then told me I could remove my clothes from the bags just a couple days later. Foolishly, I listened to him and them found more bed bugs, and now have to wash/steam all my stuff all over again (20 plus bags of laundry). Need I mention, I am also a single mother with a serious back injury, which had made this even more of a living hell!
After complaining to the company that their exterminator did a poor job, they offered to send a different one the following week as I was still finding lots (20 plus) of bed bugs crawling throughout my apartment in less than 5 days. The new guy spent about an hour treating my apartment, claimed he also checked the surrounding 4 apartments (yet it took him about 15 mins, and he said he only asked yet didn't inspect as he should have). 
On Monday it will be three weeks since my first treatment, and I have seen absolutely no improvement- it is very clear that the bed bugs have been present in the walls since before I moved in, as I have never had bed bugs before and it is also clearly a large infestation from the number of bugs I have seen and killed, too many to count!
Thus I am no voiding my lease and finding a new apartment within the next two weeks. 
Do not move into this building- over the past couple weeks I have seen plastic wrapped mattresses and couches discarded with the building's trash. Also the building is very old (full of crack and crevices in walls), and most of the tenants are elderly and speak not a word of English, so you won't have any luck finding out if they have bed bugs as well.