Four more states are joining the Justice Department’s antitrust fight against Apple

Massachusetts, Indiana, Nevada and Washington have signed on to the Justice Department’s civil antitrust lawsuit against the company Apple Inc. claiming that the tech giant monopolizes many smartphone markets.

These states have increased the number of co-plaintiffs to 20 in the Justice Department case filed in March in the U.S. District Court for the District of New Jersey.

The growing case, which initially involved 15 states and Washington, D.C., is increasing legal pressure on Apple over its business practices related to its App Store policies and alleged attempts to dominate the smartphone market.

Government officials say Apple’s iPhone monopoly gives it power…