OrgNet, a data-mining consultancy, describes how it mined the social graph of the interlocking, every changing owners of several slum-buildings to show that they were all in a criminal conspiracy to avoid having to do the legally required maintenance necessary to keeping their buildings habitable and safe.
Figure 6 shows the complete conspiracy. It was now obvious that properties exchanged hands not as independent and valid real estate investments but as a conspiracy to avoid fixing the building violations. The green links represent borrowed money flowing into the buildings through new mortgages. As time went on, and the buildings appreciated in value during a real estate boom -- loans from the mortgage company allowed the owners to "strip mine" the equity from the buildings. This is a common slumlord modus operandi -- they suck money out of a building rather than put money back in for maintenance.
...The city attorney combined the network analysis, along with the city's own extensive investigation and was able to get a conviction of key family members. Later, all of one building's tenants filed a civil suit using much of the same evidence and won a sufficient award to allow all of them to move out into decent housing. Several tenants used a part of their award to start businesses.