“This is a very peaceful town,” he said, adding that it was too early in the investigation to comment on the Kumar killings and who might be behind them.
Mosques and colorful temples are lined up next to each other here in sandy and curving alleyways. Cows, considered sacred by Hindus, roam freely on the streets, stopping at the doors of Hindu and Muslim families alike and expecting to be fed. During Ramadan, many Hindus held dinners at sunset for fasting Muslims, and Muslims frequently attended Holi and Diwali celebrations.
But as in other places in Sindh in recent years, locals have reported more activity by organizations that tend to promote a less tolerant brand of Islam and often operate as fronts for outlawed groups.
Police officers and local activists said organizations like Al Khidmat, a charity-focused branch of the Jamaat-e-Islami political party, had recently built hospitals and mosques in the area. They also said that affiliates of Jamaat-ud-Dawa — a branch of the militant group Lashkar-e-Taiba, which is accused of carrying out the deadly 2008 Mumbai attacks — as well as Lashkar-e-Jhangvi, a Sunni sectarian militant group, had made inroads into Sindh from neighboring Punjab Province.
“The spread of religious extremism is finally beginning to be felt here,” said Khatau Jani, the founder of the local press club. “Because of Thar’s centuries-old culture, it will take a long time to change our old way of living, our harmony. But yes, outsiders are coming in and people are beginning to feel afraid.”
A stone’s throw away from the press club, the shutters were down on the shop where the Kumars were killed. The flag of the Jamaat-e-Islami, one of Pakistan’s largest religious parties, flapped on the street corner.
Dozens of locals interviewed said that fear had settled in since the murders. People no longer opened their shops early in the morning, as was the norm in the town, and closed them before sunset. Women were afraid to walk alone to fetch water.
Gadhi Bhit, a popular tourist spot atop a 1,000-foot-tall sand dune frequented by sightseers looking for the best views of Mithi, stood deserted.
“They have ruined our peace of mind, the calm of our city,” said Urmila Devi, a sister of the Kumar brothers, as she received a steady procession of friends and neighbors coming to offer condolences at the Kumar home. “Now we have only our prayers. God please save us, please save Mithi.”
Dozens of women in colorful saris sat on the floor and chanted hymns. In a tiny side room, a Hindu priest recited from the ancient Bhagavad Gita as incense smoke swirled around him.
But around Mithi, members of some of the same Islamic groups that are viewed with suspicion insist that they are promoting peace.
Qurban Ali Samejo, a local leader of Jamaat-ud-Dawa, said he was “shattered” by the killing of the Kumar brothers. He was speaking in a 30-bed hospital that his organization is building in Mithi, next to a large religious school with classes underway.
Mr. Samejo said that the Falah-e-Insaniyat Foundation, a charity branch of Jamaat ud-Dawa, had done much to help communities across Tharparkar, including digging 2,000 wells and installing hundreds of water pumps and solar power cells for agricultural use. And he said the group’s aid efforts, including distributing food, helped Hindus as well.
“We go to their weddings, their funerals. Many of our constructions projects employ Hindu workers,” Mr. Samejo said. And he noted that even as a Muslim imam, he attended Diwali celebrations every year.
“It is true that in Islam this might not be permissible, but under Thari culture, you participate in your Hindu neighbors’ joys and sorrows,” he said. “In Mithi, that’s just the way of life.”
But many people here still worry that way of life is changing.
On the walls of the Thar Café, built on a roadside sand dune outside Mithi, a local rights activist, Sajid Baheer, pointed to photographs of famous musicians and poets of Mithi, many of them Hindus. One figure was Sadiq Faqir, a famous Muslim singer who died during pilgrimage to Mecca.
“Even Hindus and women attended his funeral prayers in Mithi, which is not customary at Muslim funerals,” Mr. Bajeer said. “That’s the kind of place Mithi was. Now it’s changing.”
Mr. Lal, the brothers’ uncle, said he hoped the authorities would act against the influx of “troublesome groups” before it was too late.
“Believe me, we don’t want to suspect our Muslim brothers,” he said. “But now, after what has happened, the mind lingers. Are we being sent a message? Should we leave?”