The tenant acknowledges that these activities include but are not limited to maintaining and/or using marijuanaThe Tenant shall use the premises only for residential purposes, and shall not permit any unlawful or immoral practices to be carried on and the Tenant shall not permit use of the premises in such a way as to injure their reputation in the neighbourhood, disturb other property owners, or increase the fire hazards.

A while later, I learned that another investor bought it, tenants moved in, and the cops were called to the property five times in the first two months for various tenant-caused problems (domestic disturbances, alleged drug dealing, trash being left on a neighbor's property, etc.).

If you have a multi-family, ask the operator what precautions they have in place to make sure other residents are not disturbed.

., ET ALAn article in the local paper in January painted a disturbing picture of a slumlord and likely attracted the attention of the Attorney General.  

I include in my lease that tenants and tenants guests shouldn't disturb the neighbors.

It's not the presence of lead based paint that is so much a problem with the EPA - it's doing work for a profit on a property that potentially has lead based paint and disturbing too much of that lead paint ...Whether you are a landlord or a flipper, you are seeking a profit and the EPA RRP rules apply for work that is being done.

We cannot prove it, however we are quite certain there is plenty of drug activity going on in this apartment, not to mention they are constantly disturbing other tenants with screaming.this property is located in Missouri.

Find a disturbance or improper use clause.

I can understand the seller not wanting to disturb the tenants, but I wouldn't buy without my own inspection....

This FIRE thingy / investment thingy may be cool but not worth disturbing an otherwise solid relationship.