Match Group (MTCH), the company that owns Tinder, has filed a patent infringement lawsuit in a district court in Texas, alleging that Bumble infringed on two Tinder patents: “matching process system and method,” and “display screen or portion thereof with a graphical user interface of a mobile device.” In simpler terms, the lawsuit points to design similarities between the two apps.

In addition, Match contends that some of Bumble’s features were “learned of and developed confidentially while at Tinder.” Two of Bumble’s co-creators previously worked at Tinder, at which time the suit alleges they stole confidential information, which they brought on board in the creation of the rival app.

A spokesperson for Match said that the group “has invested significant resources and creative expertise in the development of our industry-leading suite of products” and is “prepared when necessary to enforce our patents and other intellectual property rights against any operator in the dating space who infringes upon those rights.”

But some have suggested that another motive lies at the heart of the lawsuit: Match Group wants to buy Bumble. Match reportedly offered to buy Bumble for $450 million last summer, an offer which was rejected. The lawsuit therefore may be a somewhat odd bargaining chip to convince Bumble to join the company that owns the patents.

Dating service Badoo is currently majority owner of Bumble.

Correction: This story has been updated to correct an editor error that characterized Tinder as the lawsuit’s plaintiff; it is Tinder parent Match Group that filed the lawsuit.